XADM: POP3 Secure Password Authentication

Mail can not be downloaded or viewed using Microsoft Outlook Express Secure Password Authentication (SPA) to access messages on an Exchange Server computer. You may receive the following error message: This functionality requires that Exchange Server has the Windows NT Challenge/Response enabled for the POP3 protocol.

This problem may occur when a client using SPA tries to log on to a mailbox where the mailbox alias is different than the Windows NT account. The mail client uses the computer's logon credential information for SPA and assumes that the mailbox alias will be the same as the Windows NT account.

Change the users mailbox alias to match the Windows NT account in the Exchange Server Administrator program.

You can test this by telneting to port 110 of the server. After you receive the server's "ready" response from the Exchange Server computer, type "Auth NTLM," (without the quotation marks) and CRLF. If you get "+ OK," then the server supports Secure Password Authentication. Otherwise, you will receive "The NTLM Authentication package has been disabled for this protocol."