Nagios Support Forum

I have added user through ldap and he is able to login and view nagiosxi gui but when he goes to nagios core page its says that :

It appears as though you do not have permission to view information for any of the hosts you requested...
If you believe this is an error, check the HTTP server authentication requirements for accessing this CGI
and check the authorization options in your CGI configuration file.

It sounds like when the user was added to the system, they were added as a read only user and that account was not setup to view any hosts or services.
If you want that user to have the ability to view and do everything an admin account can do, then go to the Admin > Manage Users menu, edit that user and give them Admin Authorization Level rights.
If you only want them to view certain hosts / services, then you will have to add that contact to the hosts and services and the next time they login, they should only be able to see those hosts / services.
For more details on this, take a look at this document.
https://assets.nagios.com/downloads/nag ... Rights.pdf

User is able to do everything on GUI as he has admin rights.

I checked cgi.cfg file and that user does not exist on that file. Is there any problem with GUI that it is updating config file?

When a user gets created, it should update the cgi.cfg file.
Try and delete the user account and recreate it and see if the cgi file gets updated correctly this time.