Problem Description
After upgrading to Nagios XI 5.x, when you login you are presented with a white screen or a 500 error.
Resolving The Problem
In Nagios XI 5, a new LDAP component was added and is intended to replace the original Active Directory component.
In some circumstances, after upgrading the old Active Directory component causes the white screen / 500 error to appear.
To resolve the problem you need to delete the old Active Directory component.
Establish a ssh session to your XI server and execute the following:
rm -rf /usr/local/nagiosxi/html/includes/components/active_directory
Once you have deleted the old component you should be able to login.
Note: you will need to login as the nagiosadmin user as the new LDAP component will need to be configured. If you have forgotten the password to the nagiosadmin user please follow this guide:
Documentation - Resetting The nagiosadmin Password
To configure the new LDAP component please refer to this guide:
Documentation - How to Authenticate and Import Users with Active Directory
Final Thoughts
For any support related questions please visit the Nagios Support Forums at: