Symptoms:
You@yourdomain.com Task - Sending 'reported error (0 × 800CCC80):' None of the authentication methods supported by this client are supported by your server.
Problem:
You can receive email from Outlook 2007 but can not send email
Solution:
Tools => Account Settings => Double click the account => More Settings => Outgoing Server => 'Log on to incoming mail server before sending mail'
Make sure the settings for Incoming and Outgoing servers are mail.namadomain.com (namadomain.com adjust your domain name) is not your email address.
If not, go to Account Settings, select the email account and click the Repair button and follow the instructions on the screen