SMTP server refused connection?

[Kacper Wysocki <kacperw online no>]

Hi all,
I get this message quite often nowadays:

SMTP server refused connection.
Balsa by default uses submission service (587).
If you want to submit mail using relay service (25),specify it  
explicitly
via: "host:smtp".
Message is left in outbox.

This doesn't happen all the time(this message was sent using balsa),  
but often enough to be annoying. _Where_ am I supposed to specify  
"host:smtp"? I did a quick search for any related issues in (my) list  
archive, as well as looking up the manual, but I couldn't find  
anything. Does anyone have a *help_ptr?

Regards,
	Kacper