Thank you folks again for your kindness in helping me solving this problem. Al: Yes, I can connect to a different mailbox with his machine. I was thinking that it may be something related to his account on the server. If OWA is used, there's no problem. Since the mail server is located in another office, I contacted my partner and let her hnow about the problem. She launched Outlook in her machine, accessed and opened all mails from that user's mailbox. This is extremely strange to me because it looks something happening on my hand. Vicki: I used a test machine with a clean installation of Office 2000 loaded. I still get the same problem. Finally, I had to configure the user for POP access to use his email.