This is probably a rare scenario, but it helps to check “everything”, when dealing with Permissions issues in SharePoint.
I got a ticket where a user was added into a custom SharePoint User Group, and that group had Edit access to the entire site. But everything the user went to the site they were getting the error “This Site hasn’t Been Shared With You”.
First thing to check are making sure that the user’s account that has been added is really the right account. I know plenty of places where a user may have a normal account and then an admin account, or maybe they have an account in another domain and they are logged in with that other account.
After verifying that the user’s “correct” user account was listed in the SharePoint group with the correct access. I checked the Site Permissions
From here I could see that some items had unique permissions.
Clicking Show these items I saw that the site pages library may contain some unique permissions.
Of course when I checked the permissions for the site pages library it was inheriting from the top, but alas, one more alert.
Upon checking the items. I saw that 1 page in the library has custom permissions. (The Default Page nonetheless )
The custom SharePoint Group that the user was in, didn’t have any permissions the that page. That explained why users in other groups had no problems, but this particular user was affected.
After adding this custom group to the permissions for this specific page in the site pages library, it allowed the user to access the site. The error was actually a little misleading. The User did have permissions to access the site, even the library, just not the individual page in the library where the default page tried to loaded when the user accessed the site. So technically yes you did have access to the site, and if you hit a different list/library the user would have been able to get to that object without an issue.
Another pesky permissions issue. Also another reason why admin’s always try to stress the PLEASE DON’T BREAK PERMISSIONS INHERITANCE UNLESS YOU REALLY REALLY NEED TO!!!!!!. 🙂