I have a strange intermittent problem which has popped up for no apparent reason -- we use Outlook 2003 on workstations connecting to Exchange 5.5 on an NT 4 server. This morning, about 1/3 of the stations had problems connecting to Exchange. They are connected to all other programs on the network successfully, including the internet. Outlook sits there for a long time, trying to connect, when the error message pops we, we hit Retry and the connection is eventually made. However, the connection tends to go off and on, off and on. I have run a virus scan, checked for spyware, run Detect and Repair, cleaned up files on the hard drive, changed the user to an Admin account, and checked the size of their mailbox. Eventually, the connection seems to stabilize if you leave the system alone for an hour or so. No changes were made to these systems or the netwrok recently, local caching is off as is Windows Firewall. The problem machines are clumped at one end of the office, but because their overall connectivity seems fine, I doubt it is a cable problem. Any thoughts?