Verified diagnostic signature
Some challenges have failed
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
Some challenges have failedOneLiners 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