Select Accounts
Select the account you need to adjust on the left.
At the bottom on the left click on the outgoing server. It may say smtp.orcasonline.com:youremail
When you click on the server name you should get a popup, at the bottom click “Edit Server List”

In the new window click the plus sign bottom left.
At the very bottom add the server name “smtp.orcasonline.com” – leave the description alone.
Click the advanced tab click the “Use Secure Sockets Layer (SSL)”
On the Authentication: line Choose “Password”
Enter your username and password.
Click “OK”

and Close the next window making sure you save settings if requested.

During this procedure there may be a “Certificate Issue or Acceptance” screen which appears.  Approve the certificate.

Re-open the Preferences and make sure the proper outgoing server is chosen, if not, then make the change and close the window saving changes.