I use LDAP plugin to authentication, and there are two target AD Server.
Everything works fine, but recently I started seeing the logs section full of this error:

Failed communication with ldap server 6cOWbB57Lhug+DHcZ2de3w== (<<DNS name of the first server>>)
org.springframework.security.core.userdetails.UsernameNotFoundException: User <<myuser>> not found in directory.

To give full context : <<myuser>> is present in second AD server and not in the first one, but there are other user in same condition for which this error doesn't happen. I also noticed that this logs is generated even when I'm not logged in with <<myuser>> (but it always refers <<myuser>>). I can provide the full stack trace if necessary.