I looked at other similar topics, but couldn’t find the reason. I might have missed some info.
Automatic renewal of the SSL certificate has been failing for months on one of my forums. From acme.sh.log
:
[Thu Sep 18 00:32:58 UTC 2025] error='"error":{"type":"urn:ietf:params:acme:error:connection","detail":"2a01:4f8:c17:6ebb::: Fetching https://forum.tevives.fr: Timeout during connect (likely firewall problem)","status": 400'
[Thu Sep 18 00:32:59 UTC 2025] response='{
"type": "urn:ietf:params:acme:error:malformed",
"detail": "Unable to update challenge :: authorization must be pending",
"status": 400
}'
Rebuilding the app properly renews the certificate.
This is a standard install, no fancy stuff, no CDN, no reverse proxy, etc.
The firewall is set as:
Any idea why this issue happens, and how to fix it?