Two individuals can no longer be authenticated to log into Jenkins.  They are members of an extremely large number (about 950) of LDAP groups.  They have found other applications causing the same problem because those applications have an upper limit on the number of groups that can be scanned for authentication.  Does the ldap-plugin have any such limitations?  What can we check to see if this is the issue or something else is causing the problem?

Is there something I can edit in their config.xml file,  /var/lib/Jenkins/users/<user id>/config.xml, that would mitigate this?

The error message received is simply "Invalid login information.  Please try again".  We are still scouring the logs for any useful messages.