Recently i saw an issue reported by my fellow developer , when he try to add a user its throwing an exception "An error has occured in the claim providers configured for this site collection". The issue is related how central administration site (in this case central admin site but it could be any site) is accessed , he is using IP address to acces the site unfortunately there is no alternate access mapping set with IP address. So sharepoint is not able to find the provider properly.
Resolution to the issue
Configure an alternate access mapping for accessing the site.
- Go to Central administration > System Settings >Farm Management
- Under Farm Management Section Click on Configure alternate access mappings
- In alternate mapping page select the Correct web application
- Click on Add Internal URL
- Add the IP address in my case , it could be localhost / Server FQDN, depends on how you acccess the site.