I was using Firefox for my home network internal IMAP (not IMAPS) email client. I had installed Seamonkey but not used it. I opened it up, went through the account set up and it worked immediately. So it works, there might be something in your settings.
I think you must be right, but I can't work out what I've got set wrong. The mail server itself obviously works, and the users that I've set up also seem to work, since both can access the server via the webmail client.
My attempts to use the Seamonkey mail client involved changing the address (the original IMAP server was accessed by IP) to mail.domainnme.co.uk and entering the password assigned to the user on the SME box.
One odd thing that I do notice. Even though I'm fairly sure that I entered the user name in all lower case, the address of mail sent via the webmail system has come through with the username having its first letter uppercased. Is this normal, or have I got something screwed up? Unfortunately, the system is remote from me (and not running full time until we can sort the mail problem out), so I'll have to phone Ken to get him to check the user to make sure it really is 'ken' rather than 'Ken'.
Reading the docs, I see that two pseudonyms are predefined, which should be available as email addresses. I'll see if I can get Ken to set up a mail account using one of those and see if it makes any difference. He normally only uses ken@domainname.co.uk as his email address, so I'll get him to try ken.drinkwater@domainname.co.uk.
I've also set up my test box so that I can try it, though my setup is somewhat different - I don't have my own domain, and just collect mail from the POP servers of two different ISPs. Still, I should be able to interpose my SME test setup between my router/firewall and the rest of my network. I want to test the file sharing anyway - I've had problems accessing Samba shares from OS/2, and I still have an OS/2 box in my network. Also be interesting to see how easily I can access the shares from my more normal Zenwalk Linux boxes.
Hopefully someone can spot whatever stupidity it is I've committed while setting up the SME server....
paul.