- Double check your share permissions, in addition to your NTFS permissions. If people are logging in remotely the FIRST place they will run into authorization problems is in the share permissions.
- Have you tried using the “Effective Permissions” tab in the Advanced section of the security setup? This can be a helpful tool for diagnosing these kinds of problems.
- Have you given time for replication to take place? This may not matter if you are in a sufficiently small AD environment, but strange things can appear to happen if you are making changes on one DC and the users are authentication off a different one.
- Users need to log off of the domain and then back in again in order to pick up the new group membership. In most cases this will actually involve logging all the way off of their computers in order to get a new access token.