XFOR: Cannot Connect to Server with POP3 Client

You may be unable to connect to a computer running Microsoft Exchange Server with a Post Office Protocol version 3 (POP3) or Internet Messaging Access Protocol 4 (IMAP) e-mail client. No error messages are displayed.

This problem can occur when your Microsoft Exchange Server mailbox name is different from your Windows NT user name and you do not specify both names in the properties for the Microsoft Exchange Server information service. If you do not specify both names, the Microsoft Exchange Server computer may be unable to authenticate your user account and password.

To resolve this problem, specify your Windows NT domain, Windows NT user name, and Microsoft Exchange Server mailbox name in the properties for the Microsoft Exchange Server information service. To do so, follow these steps:

1. On the Tools menu in your e-mail client, click Services.
2. Click Microsoft Exchange Server in the list of information services, and then click Properties.
3. In the Mailbox box, type
   domain\username\mailbox
   where domain is your Windows NT domain, username is your Windows NT user name, and mailbox is your Microsoft Exchange Server mailbox name. For example, type:
   Domain1\User1\Mailbox1
4. Click OK, and then click OK again.

If you specify your mailbox name in the properties for the Microsoft Exchange Server information service, but do not specify your domain and user name, the computer running Microsoft Exchange Server assumes that your user name is the same as your mailbox name. If it is not, the server is unable to locate your user account.

If you specify the domain and user name, but do not specify the mailbox name, the server assumes that your mailbox name is the same as your user name. If it is not, the server is unable to locate your mailbox.