Ok, the easiest way to check to see if it is settings, or logging in with correct info, is to go to the email providers web portal and log in. If you can log in using the portla, then you know that the user name and password are correct, it would then be the cleint administration in outlook.
Make certain you are using SSL.
"If you're having trouble sending mail but you've confirmed that encryption is active for SMTP in your mail client, try to configure your SMTP server on a different port (465 or 587)."
Ok, now something that you may have to do, is authenticate againt your ISP SMTP server, in that case, you must use your ISP configuration and login.