LDAP connection doesn't work

Infos:

  • Used Zammad version: 6.4.1
  • Used Zammad installation type: (source, package, docker-compose, …): Package
  • Operating system: CentOS 9
  • Browser + version: Chome latest version 131.0.6778.140

Expected behavior:

  • I tried adding a new LDAP source, choose SSL connection type, that is supposed to work because this LDAP server works fine for other authentications over LDAPS port 636

Actual behavior:

  • Got error message: Can’t connect to ‘xxx.xxx.com’ on port ‘636’, SSL_connect returned=1 errno=0 peeraddr=(null) state=error: unexpected eof while reading

Zammad did connect to the LDAP server, I can see the connection request from the firewall log of the LDAP server and the firewall allowed the connection. But at the Zammad end, got above error.

What LDAP Server are you using?
Was the SSL handshake successful? In terms of certificate validation and matching ciphers on both systems…?