OWA IE 60 NO DOMAIN PROMPT FOR LOGIN

When using Outlook Web Access for exchange2000 via dial-in with IE 6.0 on some systems I get an additional box at the logon prompt that requests the “Domain” name in addition to user ID and password. On systems that request Domain, OWA functions OK but on systems that I do not get the Domain prompt I get partially in but get a 400 error and it will not display folders or the inbox.

What can I check or do to make the domain box appear during logon to OWA for all systems runing IE 6.0?

I’vecompared network settings ect but all seem the same.

Thanks!

Dave