I am having problems with clients logging into our Exchange (2003) server using either IMAP or POP3 using non-Outlook clients. My main goal is to get IMAP working, but in working through it, I've found that POP3 also seems to be a problem also (although I do not know if they are related). In both cases, POP3 from a GMail client and IMAP from Apple Mail, I'm simple getting an invalid login message. I do not believe this is a firewall or general connectivity issue because I can successfully telnet to the server in question (from outside the network) on both ports 110 and 143 and get the appropriate welcome messages. Both of the Exchange virtual servers are configured and running with all of the defaults. Per another thread I saw with a similar issue, I have verfied that the username and the "alias" field match for the users that I've been experimenting with. At this point I suspect that some group membership or some other user-level setting is preventing these logins but that is a guess.

Hi, Kindly confirm is the problem occurring for all user, is OWA working for these users, is GC accessible form the client on which account is configured, are these machine on domain.Ripu Daman Mina | MCSE 2003 & MCSA Messaging

Hi, 1. Open ESM, expand to Protocols->IMAP4->Default IMAP Virtual Server's properties. 2. In access tab, clear all options expect "Basic authentication". 3. Open services.msc, right click Microsoft Exchange IMAP service and choose restart. 4. When configure the mail account, input the user name as the following format: Domain\username. If the issue persists, use Domain/username instead. What's result? Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Thanks