My client's email was working fine until the end of last week. Basically they have a small workgroup of four PC's that all use Outlook (2K and XP) to send/receive email over the ADSL connection. They use their own domain name and have paid to have this domain added to the SMTP gateway of their service provider (btconnect.com).
All was fine until they decided to cancel a hosting account in error that was hosting their domain. With out going into too much detail, the domain is now active again and POP3 is working fine. The only things changed were the name servers the domain was using. The domain name is exactly the same.
Since this has happened the BT SMTP gateway is bouncing email back to the sender with the "No Transport Provider" . I've contacted BT and have been told that the domain name is definately listed on the SMTP gateway, and that I should change the Outlook setting to "My outgoing server requires auth...." with the correct log in details. I've tried this (and it's something that was not needed before this happened) but to no avail. BT won't support anything other than OE, but I'm sure it's not a client problem, rather a server problem.