Jenkins is configured to use LDAP login which works perfectly. After some time - some times directly after restarting tomcat - the login fails. When checking catalina.out the attached exception is thrown. The reason for the failed login is clear - Jenkins is configured to connect to ldap.my.domain - but when this happens Jenkins forgets "ldap" and tries to connect to my.domain only - for sure this does not work as this is no valid host name.
To fix this, we need to restart Tomcat until it failes again.