Verified diagnostic signature
urn:ietf:params:acme:error:(?:unauthorized|connection|dns|caa)
The ACME certificate authority could not prove control of at least one requested name. Match this output from certbot, then continue with sourced, read-only checks.
- Confidence
- high
- Platforms
- linux
- Verified
- 2026-07-24
Recognized output
Signature matched locally
urn:ietf:params:acme:error:(?:unauthorized|connection|dns|caa)OneLiners matches this pattern in your browser. Your pasted output is not stored or indexed.
Likely causes
What usually produces this signal
- Public A or AAAA records reach the wrong server, address, proxy, or virtual host
- TCP port 80 or the HTTP-01 challenge path is blocked, redirected incorrectly, or rewritten
- DNS-01 TXT data is absent, stale, published in the wrong zone, or not visible from every authoritative server
- CAA, DNSSEC, split DNS, or authoritative DNS availability prevents validation
Safe next checks
Collect evidence before changing the system
Resolve a hostname to its IP address
dig +short <domain>The output matches the expected target and exits without an error.
Fetch only the HTTP response headers
curl -I <url>The output matches the expected target and exits without an error.
Check whether a TCP port accepts connections
nc -vz <host> <port>The output matches the expected target and exits without an error.
Inspect a remote TLS certificate
openssl s_client -connect <host>:<port> -servername <host> </dev/null 2>/dev/null | openssl x509 -noout -subject -issuer -datesThe output matches the expected target and exits without an error.
Related signals