OT ISA 2000 not authenticating proxy clients with active directory

Ok this is OT and was seeing if any of the gurus in here have seen these:

I have an issue with our current network setup. We have ISA server 2000 on
our network for monitoring and caching. I currently have a GPO which
enforcers the use of the proxy and prevents users from changing the proxy
settings. However we have about 5 user accounts in our domain which do not
always automatically authenticate with the server. You can type in the
username and password when promted by IE to browse then internet. By using
the remember check box it works for 60 days (i.e.we have a domain policy
which requires users to change their passwords every 60 days). Any thoughts
on why ISA is not authenticating these accounts through the Active
directory?

 

Wrong newsgroup
Try posting to the "server" group