Users created cannot access accounts

Kindly assist with this issue, users cannot access accounts created, see the error message when the attempt to log on "The page isn't redirecting properly 

          Firefox has detected that the server is redirecting the request for this address in a way that will never complet.

        This problem can sometimes be caused by disabling or refusing to accept

    cookies". 

Make sure you've checked the Read Admin Panel permission for that role.