ISA server problem

Hi All,

We have an ISA server installed. Various access rules and policies have been configured assigning different access times to various users in their various categories. Whereas access is granted to most users during their assigned times, some of the users in the various categories especially those that take a while without accessing the internet cannot access the internet during their assigned times as the server will seek their authentication and even after supplying their user names and passwords, will still deny them access to the internet.

How should we go about letting these few unfortunate users have internet access?