I recently reactivated a timed out trial version of Exchange 2000 server by purchasing the software and re-installing it. All the E-mail functions work properly but the Instant messaging for some users will not let them log in. Some users work fine - (mine for instance) and the problem is not specific to the workstation but the user. I have sucessfully logged into IM on the same workstation that others can't. I have tried disabling Instant messaging on the users accounts and re-enabling it, but it didn't fix it. Any help would be appreciated.