User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040122 Debian/1.6-1 Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040122 Debian/1.6-1 POP-before-SMTP (and IMAP-before-SMTP as well) is a widely used authentication method used by providers to prevent spamming. It has nothing to do with regular SMTP-Authentication. Various other Mail readers have an option which automates the task Mozilla users have to do by hand: Checking mail before being able to send some. Reproducible: Always Steps to Reproduce: 0. Keep unconnected to the net (Affects mostly dial-up-users). 1. Open Mailnews. (e.g. by using mozilla -mail -compose) 2. Connect to your provider that uses DRAC/popbsmtp 3. Try to send a mail Actual Results: Your SMTP server responds that you have to check mail before being able to send. You have switch to inbox and click on "get messages" manually. Retrying to send will work now. Expected Results: If sending fails, mozilla should try to fetch mail automatically in the background. If sending then works, we know that pop/imap-before-smtp is used by that smtp-server. Set a corresponding userpref that will do the MailCheck automatically in the future, whenever a mail is to be sent via that smtp server. SHAME ON ME. This is a dup of Bug #81387 (Filed Mid-2001, unresolved). Sorry for conciously filing an existing bug, but I only need a little hint if my approach/fix is correct by anyone actively maintaining the source. Read comment #20 of that bug, give me a hint, and hate me for filing a dup... Just did it to get an active maintainer involved here, providing hints. Seems nobody from the #81387-CC-list is still active on that quite important bug (or better "year-old-easily-to-solve-RFE"). Many urls provided on that topic in dup Bug #81387, Comment #20.

*** This bug has been marked as a duplicate of 81387 ***