diff --git a/daemon/client.py b/daemon/client.py
index e0e2b04..679349b 100644
--- a/daemon/client.py
+++ b/daemon/client.py
@@ -35,6 +35,12 @@ class BadRequest(Exception):
     pass
 
 
+class Conflict(Exception):
+    """Raised when the daemon returns HTTP 409."""
+
+    pass
+
+
 _DEFAULT_SOCKET = None
 
 
@@ -175,6 +181,8 @@ def request(
                 raise NotFound(data.get("error", str(exc))) from exc
             if resp.status_code == 400:
                 raise BadRequest(data.get("error", str(exc))) from exc
+            if resp.status_code == 409:
+                raise Conflict(data.get("error", str(exc))) from exc
             raise RuntimeError(data.get("error", str(exc))) from exc
     if not data.get("ok"):
         raise RuntimeError(data.get("error", "Unknown error"))
diff --git a/daemon/handlers/acme.py b/daemon/handlers/acme.py
index d411458..8f751b2 100644
--- a/daemon/handlers/acme.py
+++ b/daemon/handlers/acme.py
@@ -15,6 +15,7 @@ from pathlib import Path
 from typing import Any
 from uuid import uuid4
 
+import lib.acme
 import lib.common as lib_common
 from daemon.iface import (
     DELETE_ACME_ACCOUNT_DEACTIVATE,
@@ -32,8 +33,8 @@ from daemon.iface import (
     POST_ACME_SELF_SIGNED,
     POST_ACME_VALIDATE,
 )
-from daemon.server import NotFoundError, refresh_state, registry
-from lib.state import _run_acme
+from daemon.server import ConflictError, NotFoundError, refresh_state, registry
+from lib.acme import _run_acme
 
 logger = logging.getLogger(__name__)
 
@@ -55,6 +56,14 @@ _ISSUANCES: dict[str, "IssueRequest"] = {}
 _ISSUANCE_TTL = 300  # seconds to keep completed requests
 
 
+def _find_issuance(domain: str) -> "IssueRequest | None":
+    """Find an active (running) issuance request by domain."""
+    for req in _ISSUANCES.values():
+        if req.domain == domain and req.status == "running":
+            return req
+    return None
+
+
 @dataclass
 class IssueStep:
     """Single step in a certificate issuance workflow.
@@ -122,7 +131,7 @@ class IssueRequest:
 
 def _find_acme_bin() -> str:
     """Return the path to the acme.sh binary."""
-    from lib.state import _find_acme
+    from lib.acme import _find_acme
 
     return _find_acme()
 
@@ -332,13 +341,11 @@ def _check_challenge_config() -> tuple[bool, str]:
 def _check_existing_cert(domain: str) -> tuple[bool, str]:
     """Warn if a valid cert already exists (not blocking)."""
     try:
-        from lib.acme import days_until_expiry
-
-        days = days_until_expiry(domain)
-        if days is not None and days > 0:
-            return True, f"Valid certificate exists ({days} days remaining)"
-    except (ValueError, RuntimeError, FileNotFoundError):
-        pass
+        days = lib.acme.days_until_expiry(domain)
+    except (RuntimeError, FileNotFoundError):
+        return True, ""
+    if days is not None and days > 0:
+        return True, f"Valid certificate exists ({days} days remaining)"
     return True, ""
 
 
@@ -660,9 +667,23 @@ def get_cert_info(_request: Any, body: dict[str, Any] | None) -> dict:
         raise ValueError("'domain' is required")
     domain = body["domain"]
     certs = list_certs(None, None)
+    req = _find_issuance(domain)
+
     for c in certs:
         if c["domain"] == domain or domain in c.get("san_domains", []):
-            return c
+            result = dict(c)
+            if req:
+                result["issuance"] = req.to_dict()
+            return result
+
+    # No cert found — check if there's an in-progress issuance
+    if req:
+        return {
+            "domain": domain,
+            "status": "issuing",
+            "issuance": req.to_dict(),
+        }
+
     raise NotFoundError(f"No certificate found for domain: {domain}")
 
 
@@ -689,7 +710,6 @@ async def issue_cert(_request: Any, body: dict[str, Any] | None) -> dict[str, An
 
     Raises:
         ValueError: When domain is missing.
-        RuntimeError: When pre-flight checks fail.
     """
     if not body:
         raise ValueError("Request body required")
@@ -707,16 +727,28 @@ async def issue_cert(_request: Any, body: dict[str, Any] | None) -> dict[str, An
 
     _clean_expired_issuances()
 
-    # Dedup: if domain already has an active request, return existing ID
+    # Dedup: if domain already has an active request, return it
     for existing in _ISSUANCES.values():
         if existing.domain == domain and existing.status == "running":
             return {
                 "request_id": existing.request_id,
-                "status": "existing",
                 "domain": domain,
-                "message": "Issuance already in progress for this domain",
+                "status": "existing",
             }
 
+    # Check if cert already exists — call acme.sh directly, not via state
+    try:
+        certs = lib.acme.list_certs()
+    except RuntimeError as exc:
+        raise RuntimeError(f"Cannot check existing certificates: {exc}") from exc
+    for c in certs:
+        if c["domain"] == domain or domain in c.get("san_domains", []):
+            days = c.get("days_until_expiry")
+            if days is not None and days >= 0:
+                raise ConflictError(
+                    f"Certificate already exists for {domain} ({days} day{'s' if days != 1 else ''} remaining). Renew instead."
+                )
+
     # Run pre-flight checks
     _validate_checks = _validate(domain)
     if not _validate_checks["ready"]:
diff --git a/daemon/server.py b/daemon/server.py
index 7107dfb..57688a4 100644
--- a/daemon/server.py
+++ b/daemon/server.py
@@ -159,6 +159,12 @@ class NotFoundError(Exception):
     pass
 
 
+class ConflictError(Exception):
+    """Raised when a request conflicts with an existing resource."""
+
+    pass
+
+
 def ok(data: Any = None) -> web.Response:
     """Create a success JSON response.
 
@@ -247,6 +253,8 @@ async def _handle_request(request: web.Request) -> web.Response:
                 result = await result
     except NotFoundError as exc:
         return error(str(exc), 404)
+    except ConflictError as exc:
+        return error(str(exc), 409)
     except ValueError as exc:
         return error(str(exc), 400)
     except RuntimeError as exc:
@@ -420,10 +428,10 @@ async def _poll_loop(subsystem: str, interval: int) -> None:
         await asyncio.sleep(interval)
 
 
-def start_polling() -> None:
+def start_polling(loop: asyncio.AbstractEventLoop) -> None:
     """Start one poll loop task per subsystem."""
     for subsystem, interval in _POLL_INTERVALS.items():
-        task = asyncio.create_task(_poll_loop(subsystem, interval))
+        task = loop.create_task(_poll_loop(subsystem, interval))
         task.add_done_callback(_poll_tasks.discard)
         _poll_tasks.add(task)
 
@@ -547,7 +555,7 @@ def main() -> None:
     for subsystem in state_store.SUBSYSTEMS:
         if state_store.get(subsystem) is not None:
             state_store.bump(subsystem)
-    loop.run_until_complete(start_polling())
+    start_polling(loop)
     logger.info("vacuum-walld listening on %s", socket_path)
     logger.info("WebSocket on 127.0.0.1:%d", _WS_PORT)
 
diff --git a/lib/acme.py b/lib/acme.py
index 1851509..51116f8 100644
--- a/lib/acme.py
+++ b/lib/acme.py
@@ -257,7 +257,7 @@ def list_certs() -> list[dict]:
             continue
 
         san_domains = [
-            d.strip() for d in entry.get("san_domain", "").split(",") if d.strip()
+            d.strip() for d in entry.get("san_domains", "").split(",") if d.strip()
         ]
 
         cert_dir = acme_home / main
@@ -265,21 +265,21 @@ def list_certs() -> list[dict]:
         key_path = str(cert_dir / f"{main}.key")
         ca_path = str(cert_dir / "ca.cer")
 
-        days = _days_until(entry.get("certificate_expires", ""))
+        days = _days_until(entry.get("renew", ""))
         auto = _has_auto_renew(main)
 
         certs.append(
             {
                 "domain": main,
-                "issuer": entry.get("CA", ""),
-                "expiry": entry.get("certificate_expires", ""),
+                "issuer": entry.get("ca", ""),
+                "expiry": entry.get("renew", ""),
                 "days_remaining": days,
                 "expired": days is not None and days <= 0,
                 "cert_path": cert_path,
                 "key_path": key_path,
                 "ca_path": ca_path,
-                "issued_at": entry.get("certificate_date", ""),
-                "expires_at": entry.get("certificate_expires", ""),
+                "issued_at": entry.get("created", ""),
+                "expires_at": entry.get("renew", ""),
                 "days_until_expiry": days,
                 "auto_renew": auto,
                 "san_domains": san_domains,
@@ -437,28 +437,57 @@ def deploy(domain: str) -> None:
 # ------------------------------------------------------------------
 
 
+def _split_line(line: str, separator: str | None) -> list[str]:
+    """Split a line by *separator*, falling back to whitespace for column output."""
+    if separator in line:
+        return line.split(separator)
+    return line.split()
+
+
 def _parse_list_output(raw: str) -> list[dict]:
-    """Parse the text output from ``acme.sh --list`` into a list of dicts.
+    """Parse output from ``acme.sh --list`` into a list of dicts.
 
-    Each line in the output contains ``Key:Value`` tokens separated by
-    whitespace, e.g.::
+    Handles three formats depending on system capabilities:
+    - Raw pipe-separated output (``|``)
+    - Tab-separated output (when ``column`` is unavailable)
+    - Column-aligned output (when ``column`` is available)
 
-        Main_Domain:example.com SAN_Domain:www.example.com CA:Let's
-        Encrypt Certificate_Date:2026-04-01 Certificate_Expired:No
-
-    Keys are converted to lowercase in the returned dicts.
+    All formats share the same header: Main_Domain, KeyLength, SAN_Domains,
+    Profile, CA, Created, Renew.
     """
+    lines = raw.strip().splitlines()
+
+    if len(lines) < 2:
+        return []
+
+    header_line = lines[0]
+
+    # Detect separator from header: pipe, tab, or whitespace
+    if "|" in header_line:
+        headers = _split_line(header_line, "|")
+        separator = "|"
+    elif "\t" in header_line:
+        headers = _split_line(header_line, "\t")
+        separator = "\t"
+    else:
+        headers = _split_line(header_line, None)  # whitespace
+        separator = None
+
+    if "Main_Domain" not in headers:
+        raise ValueError(
+            f"acme.sh --list output is not in expected format: {header_line!r}"
+        )
+
     entries: list[dict] = []
-    for line in raw.strip().splitlines():
+    for line in lines[1:]:
         line = line.strip()
         if not line:
             continue
+        fields = _split_line(line, separator)
         entry: dict[str, str] = {}
-        for token in line.split():
-            if ":" not in token:
-                continue
-            key, _, value = token.partition(":")
-            entry[key.lower()] = value
+        for i, h in enumerate(headers):
+            if i < len(fields):
+                entry[h.lower()] = fields[i].strip().strip('"')
         if entry:
             entries.append(entry)
     return entries
diff --git a/lib/state.py b/lib/state.py
index 5b2248b..31df1a7 100644
--- a/lib/state.py
+++ b/lib/state.py
@@ -7,8 +7,6 @@ state instead of invoking subprocesses on every request.
 import contextlib
 import logging
 import os
-import shutil
-import subprocess
 from copy import deepcopy
 from datetime import UTC, datetime
 from pathlib import Path
@@ -28,6 +26,11 @@ logger = logging.getLogger(__name__)
 
 PROJECT_DIR = Path(__file__).resolve().parent.parent
 
+_CA_NAME_MAP: dict[str, str] = {
+    "letsencrypt": "Let's Encrypt",
+    "zerossl": "ZeroSSL",
+}
+
 _DEFAULT_POLL_INTERVALS: dict[str, int] = {
     "firewall": 30,
     "wireguard": 10,
@@ -677,113 +680,25 @@ register_collector("nginx", _collect_nginx)
 # ---------------------------------------------------------------------------
 
 
-def _find_acme() -> str:
-    """Locate the ``acme.sh`` binary on the filesystem.
+def _resolve_ca_name(ca_server: str) -> str:
+    """Map a CA server identifier to its human-readable name.
 
-    Returns:
-        Absolute path to the ``acme.sh`` executable.
-
-    Raises:
-        FileNotFoundError: If acme.sh cannot be found.
-    """
-    acme_home = PROJECT_DIR / "data" / "acme"
-    candidates = [acme_home / "acme.sh", Path("/usr/local/bin/acme.sh")]
-    for path in candidates:
-        if path.is_file() and os.access(path, os.X_OK):
-            return str(path)
-    acme = shutil.which("acme.sh")
-    if acme:
-        return acme
-    raise FileNotFoundError("acme.sh not found")
-
-
-def _run_acme(args: list[str]) -> str:
-    """Run ``acme.sh`` with *args* and return combined output.
+    Uses prefix matching sorted by longest prefix first to avoid
+    shorter prefixes winning (e.g. "letsencrypt" matching before
+    "letsencrypt.org").
 
     Args:
-        args: Command-line arguments to pass after the home/config flags.
+        ca_server: Raw CA server string from acme.sh config.
 
     Returns:
-        Combined stdout/stderr output.
-
-    Raises:
-        RuntimeError: If acme.sh exits non-zero or times out.
+        Human-readable name, or unchanged string if no match.
     """
-    acme_bin = _find_acme()
-    acme_home_env = os.environ.get("ACME_HOME", str(PROJECT_DIR / "data" / "acme"))
-    cmd = [acme_bin, "--home", acme_home_env, "--config-home", acme_home_env, *args]
-    _ACME_ENVIRON = {
-        "HOME": str(PROJECT_DIR),
-        "PATH": os.environ.get(
-            "PATH", "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
-        ),
-    }
-    try:
-        result = subprocess.run(
-            cmd,
-            capture_output=True,
-            text=True,
-            timeout=120,
-            env={**os.environ, **_ACME_ENVIRON},
-        )
-    except subprocess.TimeoutExpired as exc:
-        raise RuntimeError(f"acme.sh timed out: {' '.join(cmd)}") from exc
-    output = result.stdout
-    if result.stderr:
-        output = output + result.stderr if output else result.stderr
-    if result.returncode != 0:
-        raise RuntimeError(f"acme.sh failed (rc={result.returncode}): {output.strip()}")
-    return output
-
-
-def _days_until(date_str: str) -> int | None:
-    """Parse a date string and return days until *date_str* from now.
-
-    Args:
-        date_str: Date string in common ACME formats.
-
-    Returns:
-        Number of days remaining, or ``None`` if empty or unparseable.
-    """
-    if not date_str:
-        return None
-    for fmt in ("%Y-%m-%d", "%Y-%m-%dT%H:%M:%S"):
-        try:
-            dt = datetime.strptime(date_str, fmt).replace(tzinfo=UTC)
-            return (dt - datetime.now(UTC)).days
-        except ValueError:
-            continue
-    try:
-        dt = datetime.strptime(date_str, "%Y%m%d%H%M%z").astimezone(UTC)
-        return (dt - datetime.now(UTC)).days
-    except ValueError:
-        pass
-    return None
-
-
-def _parse_acme_list_output(raw: str) -> list[dict]:
-    """Parse ``acme.sh --list`` output into a list of certificate dicts.
-
-    Args:
-        raw: Raw output string from ``acme.sh --list``.
-
-    Returns:
-        List of dicts with certificate entry fields.
-    """
-    entries: list[dict] = []
-    for line in raw.strip().splitlines():
-        line = line.strip()
-        if not line:
-            continue
-        entry: dict[str, str] = {}
-        for token in line.split():
-            if ":" not in token:
-                continue
-            key, _, value = token.partition(":")
-            entry[key.lower()] = value
-        if entry:
-            entries.append(entry)
-    return entries
+    for prefix, name in sorted(
+        _CA_NAME_MAP.items(), key=lambda x: len(x[0]), reverse=True
+    ):
+        if ca_server.startswith(prefix):
+            return name
+    return ca_server
 
 
 def _parse_account_conf(acme_home: Path | None = None) -> dict[str, Any]:
@@ -834,11 +749,7 @@ def _parse_account_conf(acme_home: Path | None = None) -> dict[str, Any]:
     if not email or not ca_raw:
         return default
 
-    ca_map = {
-        "letsencrypt": "Let's Encrypt",
-        "zerossl": "ZeroSSL",
-    }
-    ca = ca_map.get(ca_raw, ca_raw)
+    ca = _resolve_ca_name(ca_raw)
 
     return {
         "registered": True,
@@ -848,19 +759,6 @@ def _parse_account_conf(acme_home: Path | None = None) -> dict[str, Any]:
     }
 
 
-def _has_auto_renew(domain: str) -> bool:
-    """Check whether *domain* has an auto-renew configuration file.
-
-    Args:
-        domain: Domain name to check.
-
-    Returns:
-        ``True`` if a corresponding ``acme.sh`` config file exists.
-    """
-    acme_home_env = os.environ.get("ACME_HOME", str(PROJECT_DIR / "data" / "acme"))
-    return bool(Path(acme_home_env) / f"{domain}.conf")
-
-
 def _get_acme_email() -> str:
     """Read the ACME ``acme.sh`` email from the account config file.
 
@@ -882,8 +780,16 @@ def _collect_acme() -> dict[str, Any]:
 
     certs: list[dict[str, Any]] = []
     try:
+        from lib.acme import (
+            _days_until,
+            _has_auto_renew,
+            _parse_list_output,
+            _run_acme,
+        )
+
         raw = _run_acme(["--list"])
-        entries = _parse_acme_list_output(raw)
+
+        entries = _parse_list_output(raw)
         acme_home_env = os.environ.get("ACME_HOME", str(PROJECT_DIR / "data" / "acme"))
         acme_home = Path(acme_home_env)
         for entry in entries:
@@ -891,29 +797,33 @@ def _collect_acme() -> dict[str, Any]:
             if not main:
                 continue
             san_domains = [
-                d.strip() for d in entry.get("san_domain", "").split(",") if d.strip()
+                d.strip() for d in entry.get("san_domains", "").split(",") if d.strip()
             ]
             cert_dir = acme_home / main
-            days = _days_until(entry.get("certificate_expires", ""))
+            days = _days_until(entry.get("renew", ""))
             certs.append(
                 {
                     "domain": main,
-                    "issuer": entry.get("CA", ""),
-                    "expiry": entry.get("certificate_expires", ""),
+                    "issuer": entry.get("ca", ""),
+                    "expiry": entry.get("renew", ""),
                     "days_remaining": days,
                     "expired": days is not None and days <= 0,
                     "cert_path": str(cert_dir / "fullchain.cer"),
                     "key_path": str(cert_dir / f"{main}.key"),
                     "ca_path": str(cert_dir / "ca.cer"),
-                    "issued_at": entry.get("certificate_date", ""),
-                    "expires_at": entry.get("certificate_expires", ""),
+                    "issued_at": entry.get("created", ""),
+                    "expires_at": entry.get("renew", ""),
                     "days_until_expiry": days,
                     "auto_renew": _has_auto_renew(main),
                     "san_domains": san_domains,
                 }
             )
     except Exception:
-        pass
+        logger.warning(
+            "ACME state collection failed, returning empty cert list",
+            exc_info=True,
+        )
+        raise
 
     account = _parse_account_conf()
 
diff --git a/system/sudoers.d/vacuum-walld b/system/sudoers.d/vacuum-walld
index 10b8a11..2c10a76 100644
--- a/system/sudoers.d/vacuum-walld
+++ b/system/sudoers.d/vacuum-walld
@@ -14,6 +14,7 @@ Defaults:{{ USER_DAEMON_NAME }} secure_path="/usr/local/sbin:/usr/local/bin:/usr
 {{ USER_DAEMON_NAME }} ALL=(root) NOPASSWD: /usr/bin/cp * /etc/nginx/snippets/*
 {{ USER_DAEMON_NAME }} ALL=(root) NOPASSWD: /usr/bin/rm /etc/nginx/conf.d/vacuum-wall.conf
 {{ USER_DAEMON_NAME }} ALL=(root) NOPASSWD: /usr/bin/rm /etc/nginx/snippets/vacuum-wall-ssl.conf
+{{ USER_DAEMON_NAME }} ALL=(root) NOPASSWD: /usr/bin/chown root\:root /etc/nginx/conf.d/vacuum-wall.conf
 {{ USER_DAEMON_NAME }} ALL=(root) NOPASSWD: /usr/bin/chown root\:root /etc/nginx/snippets/vacuum-wall-ssl.conf
 
 # Dnsmasq management
diff --git a/system/systemd/vacuum-walld.service b/system/systemd/vacuum-walld.service
index 4758f5b..a9674b5 100644
--- a/system/systemd/vacuum-walld.service
+++ b/system/systemd/vacuum-walld.service
@@ -19,7 +19,7 @@ Environment=HOME={{ PROJECT_DIR }}
 
 # Security hardening
 ProtectSystem=strict
-ReadWritePaths={{ PROJECT_DIR }} /tmp /etc/systemd/network /etc/nginx /etc/dnsmasq.d /etc/wireguard /run/sudo /run/firewalld /run/nginx
+ReadWritePaths={{ PROJECT_DIR }} /tmp /etc/systemd/network /etc/nginx /etc/dnsmasq.d /etc/wireguard /run/sudo /run/firewalld /run/nginx /run/nginx.pid /var/log/nginx
 PrivateTmp=yes
 ProtectKernelTunables=yes
 ProtectKernelModules=yes
diff --git a/tests/test_acme.py b/tests/test_acme.py
index 35c7a97..07fa812 100644
--- a/tests/test_acme.py
+++ b/tests/test_acme.py
@@ -61,17 +61,14 @@ class TestRunAcme:
 
 class TestParseListOutput:
     def test_parses_single_entry(self):
-        raw = "Main_Domain:example.com CA:LetsEncrypt Certificate_Date:2026-04-01 Certificate_Expires:2026-07-01 Certificate_Expired:No"
+        raw = "Main_Domain\tCA\nexample.com\tLetsEncrypt\n"
         result = acme._parse_list_output(raw)
         assert len(result) == 1
         assert result[0]["main_domain"] == "example.com"
         assert result[0]["ca"] == "LetsEncrypt"
 
     def test_parses_multiple_entries(self):
-        raw = (
-            "Main_Domain:a.com CA:LE Certificate_Expires:2026-07-01 Certificate_Expired:No\n"
-            "Main_Domain:b.com CA:LE Certificate_Expires:2026-08-01 Certificate_Expired:No"
-        )
+        raw = "Main_Domain\tCA\na.com\tLE\nb.com\tLE\n"
         result = acme._parse_list_output(raw)
         assert len(result) == 2
 
@@ -79,10 +76,46 @@ class TestParseListOutput:
         result = acme._parse_list_output("")
         assert result == []
 
-    def test_skips_lines_without_colons(self):
-        raw = "some random line\nMain_Domain:a.com"
+    def test_skips_empty_lines(self):
+        raw = "Main_Domain\tCA\nexample.com\tLE\n\n   \nother.com\tLE\n"
+        result = acme._parse_list_output(raw)
+        assert len(result) == 2
+
+    def test_header_skipped(self):
+        """Header row is not included in results."""
+        raw = "Main_Domain\tKeyLength\tCA\nexample.com\tec-256\tZeroSSL.com\n"
         result = acme._parse_list_output(raw)
         assert len(result) == 1
+        assert result[0]["main_domain"] == "example.com"
+
+    def test_field_mapping(self):
+        """Tab columns are mapped to lowercased header names as dict keys."""
+        raw = (
+            "Main_Domain\tKeyLength\tSAN_Domains\tProfile\tCA\tCreated\tRenew\n"
+            'example.com\t"ec-256"\twww.example.com\t\tZeroSSL.com\t2026-01-01\t2026-07-01\n'
+        )
+        result = acme._parse_list_output(raw)
+        assert len(result) == 1
+        entry = result[0]
+        assert entry["main_domain"] == "example.com"
+        assert entry["keylength"] == "ec-256"
+        assert entry["san_domains"] == "www.example.com"
+        assert entry["profile"] == ""
+        assert entry["ca"] == "ZeroSSL.com"
+        assert entry["created"] == "2026-01-01"
+        assert entry["renew"] == "2026-07-01"
+
+    def test_quoted_values_stripped(self):
+        """Quoted values have quotes removed."""
+        raw = 'Main_Domain\tKeyLength\nexample.com\t"ec-256"\n'
+        result = acme._parse_list_output(raw)
+        assert result[0]["keylength"] == "ec-256"
+
+    def test_header_only(self):
+        """Header with no data rows returns empty list."""
+        raw = "Main_Domain\tKeyLength\tCA\n"
+        result = acme._parse_list_output(raw)
+        assert result == []
 
 
 class TestDaysUntil:
diff --git a/tests/test_handler_acme.py b/tests/test_handler_acme.py
index 006d1cb..5aa8731 100644
--- a/tests/test_handler_acme.py
+++ b/tests/test_handler_acme.py
@@ -1,5 +1,6 @@
 """Tests for daemon/handlers/acme.py — handler endpoint logic."""
 
+import asyncio
 import urllib.error
 from pathlib import Path
 from unittest.mock import MagicMock, patch
@@ -24,8 +25,10 @@ from daemon.handlers.acme import (
     deactivate_account,
     generate_self_signed,
     get_account,
+    issue_cert,
     register_account,
 )
+from daemon.server import ConflictError
 
 
 class TestGenerateSelfSigned:
@@ -1088,3 +1091,64 @@ class TestDeactivateAccount:
 
         assert not (acme_dir / ".account.conf").is_file()
         assert not (acme_dir / "account.conf").is_file()
+
+
+class TestIssueCertExistingCerts:
+    """Phase 3: issue_cert blocks when cert expires today (days == 0) or tomorrow (days == 1)."""
+
+    def test_days_zero_blocks(self):
+        """days_until_expiry returns 0 (expires today) — should block."""
+        with (
+            patch(
+                "daemon.handlers.acme._validate",
+                return_value={"ready": True, "checks": []},
+            ),
+            patch(
+                "lib.acme.list_certs",
+                return_value=[{"domain": "example.com", "days_until_expiry": 0}],
+            ),
+            pytest.raises(ConflictError, match="0 days remaining"),
+        ):
+            asyncio.run(issue_cert(None, {"domain": "example.com"}))
+
+    def test_days_one_blocks(self):
+        """days_until_expiry returns 1 (expires tomorrow) — should still block."""
+        with (
+            patch(
+                "daemon.handlers.acme._validate",
+                return_value={"ready": True, "checks": []},
+            ),
+            patch(
+                "lib.acme.list_certs",
+                return_value=[{"domain": "example.com", "days_until_expiry": 1}],
+            ),
+            pytest.raises(ConflictError, match="1 day remaining"),
+        ):
+            asyncio.run(issue_cert(None, {"domain": "example.com"}))
+
+    def test_days_negative_one_allows(self):
+        """days_until_expiry returns -1 (already expired) — should not block."""
+
+        async def _fake_run_issue(req):
+            pass
+
+        with (
+            patch(
+                "daemon.handlers.acme._validate",
+                return_value={"ready": True, "checks": []},
+            ),
+            patch(
+                "lib.acme.list_certs",
+                return_value=[{"domain": "example.com", "days_until_expiry": -1}],
+            ),
+            patch.dict("daemon.handlers.acme._ISSUANCES", clear=True),
+            patch(
+                "daemon.handlers.acme._run_issue",
+                new=MagicMock(side_effect=_fake_run_issue),
+            ) as mock_run_issue,
+        ):
+            result = asyncio.run(issue_cert(None, {"domain": "example.com"}))
+
+        assert result["domain"] == "example.com"
+        assert "request_id" in result
+        mock_run_issue.assert_called_once()
diff --git a/webui/api/certs.py b/webui/api/certs.py
index 550ee67..b02ba16 100644
--- a/webui/api/certs.py
+++ b/webui/api/certs.py
@@ -7,7 +7,7 @@ import logging
 
 from flask import Blueprint, request
 
-from daemon.client import BadRequest, NotFound, delete, get, post
+from daemon.client import BadRequest, Conflict, NotFound, delete, get, post
 from daemon.iface import (
     DELETE_ACME_ACCOUNT_DEACTIVATE,
     DELETE_ACME_REMOVE,
@@ -114,6 +114,8 @@ def issue_start():
     except BadRequest as exc:
         logger.info("Cert issue for '%s' rejected: %s", domain, exc)
         return _error(str(exc), 400)
+    except Conflict as exc:
+        return _error(str(exc), 409)
     except RuntimeError as exc:
         logger.error("Failed to start cert issue for '%s': %s", domain, exc)
         return _error(str(exc), 500)
diff --git a/webui/static/pages/certs.js b/webui/static/pages/certs.js
index aa46c28..49b962c 100644
--- a/webui/static/pages/certs.js
+++ b/webui/static/pages/certs.js
@@ -236,7 +236,12 @@ function _bindIssueButtons(inner, modalIdx) {
         const body = { domain: _currentIssueState.domain };
         const issueResp = await apiFetch('/api/certs/issue/start', { method: 'POST', body });
         if (issueResp.ok) {
-            toast('Issuance started for ' + _currentIssueState.domain, 'success');
+            const status = issueResp.data?.status;
+            if (status === 'existing') {
+                toast('Issuance already in progress for ' + _currentIssueState.domain, 'warning');
+            } else {
+                toast('Issuance started for ' + _currentIssueState.domain, 'success');
+            }
             closeModal(modalIdx);
             const rid = issueResp.data?.request_id;
             if (rid) pollCertIssue(rid);