As I laid out in this post on November 5th, the mail client on the Surface RT had some configuration issues that would not allow some of us to send email.
There was an update released on 12/20/2012 that updated the mail client and required a reboot. This seems to have fixed the issue, which is great! I can now send email from my personal email account on the Surface RT.
I initially tried to simply change/reapply my settings, and it did not work for me. I eventually had to delete the account from the mail app, reboot, and re-add the account. That worked.
Finally.
