Problem  - Error Using SSRS Reports on Anonymous SharePoint site "The permissions granted to user 'NT AUTHORITY\IUSR' are insufficient for performing this operation"

Soltuion -

·         Click on the 'Security' tab à 'Edit' (under groups and users) à 'Add' (under groups and users). This brings you to the 'Select Users, Computers, Service Accounts, or Groups' window.


·         Click on the 'Object Types...' button and just select everything and hit 'OK'.


·         Next, click on 'Locations ...' and select the parent-most option (this will most likely be the server itself) and hit 'OK'

·         Next, click on the 'Advanced' button and select the 'Find Now' button.


·         You will see several search results. Within this list, you will find the IUSR username. Select it, and hit 'OK' and grant him FULL permissions.