I just downloaded and configured CONE the mail user agent, and everything seemed awesome until I realized that I couldn't send email. Whenever I tried to send email via my mailshack.com pop account I got this error:
550 This user account is not authorized to send messages with the address user@myComputer.
As you can see, it is trying to send email via the correct server (mailshack's server) but it is using my linux login and computer name for the return address, and of course mailshack.com has a policy against this.
From the SETUP menu, I deleted ALL references to user@myComputer and replaced them with myEmailAccount@ m a i l s h a c k . c o m, I then manually deleted any reference to user@mycomputer by opening ~/.cone/conerc with a text editor.
I can't paste my conerc because I'm ssh'ing into my computer via putty, and it doesn't let me do that. (at least without jumping through ten hoops)
Anyway, in the off-chance that this has happened to someone here, and they found a solution, please let me know how you resolved it.