You can access the Nagios XI interface, but can't seem to access the Core Configuration Manager.
Access the Admin >Reset Security Credentials page and reset the subsystem credentials.
Run the following command from the shell:
For any support related questions please visit the Nagios Support Forums at:
Article ID: 151
Created On: Mon, Jan 25, 2016 at 10:15 PM
Last Updated On: Mon, Feb 22, 2016 at 7:30 PM
Authored by: tlea
Online URL: https://support.nagios.com/kb/article/nagios-xi-resolving-cannot-connect-to-database-error-core-config-manager-151.html