[guenter]

Thanks for your help, the Yahoo login is now working fine, but I still get the proplem with the Pop3/SMTP login. I have checked the connection details a few times and have also re-set the password just to be sure.

I have below two entries from the qmail server log, the first one is a successful login with Windows Mail, the second one is generated by clicking on 'Save Settings' in Zimbra:

Sep 9 14:32:25 abc123 pop3d: Connection, ip=[XX.XX.XX.XXX]
Sep 9 14:32:25 abc123 pop3d: IMAP connect from @ [XX.XX.XX.XXX]INFO: LOGIN, user=user@domain.org, ip=[XX.XX.XX.XXX]
Sep 9 14:32:25 abc123 pop3d: 1220988745.970748 LOGOUT, user=user@domain.org, ip=[XX.XX.XX.XXX], top=0, retr=0, time=0, rcvd=12, sent=39, maildir=/var/qmail/mailnames/domain.org/admin/Maildir



Sep 9 14:32:42 abc123 pop3d: Connection, ip=[XX.XX.XX.XXX]
Sep 9 14:32:42 abc123 pop3d: IMAP connect from @ [XX.XX.XX.XXX]INFO: LOGIN, user=user@domain.org, ip=[XX.XX.XX.XXX]
Sep 9 14:32:43 abc123 pop3d: 1220988763.455062 DISCONNECTED, user=user@domain.org, ip=[XX.XX.XX.XXX], top=0, retr=0, time=1, rcvd=12, sent=25, maildir=/var/qmail/mailnames/domain.org/admin/Maildir

The main difference seems to be the 'LOGOUT' on Windows Mail, and the 'DISCONNECTED' in the Zimbra connection. I don't know if this will help to solve the problem - any help is greatly appreciated.