Outlook Express works properly so it shouldn't be a "name resolution, IP connectivity, & firewall configuration" issue.

PS This mailing system is really obsole. I'd love to have a true discussion forum.

Is OTRS on on a windows platform!? If not I'd verify that name resolution is the same from your Outlook Express system as the OTRS server/host.

Shouldn't be doesn't mean that it isn't. check that you can connect to the mail server from the OTRS box (telnet <server_hostname> 110).

RE:PS - I assume that the mailing list is (1) more cost effective & (2) forces members to see issue. I am on registered on several web discussions which I often forget to visit.