Open Outlook email application. Go to the "Tools" menu and select "E-Mail Accounts".
Select "View or change existing e-mail accounts", click "Next".
Select the account that requires a change, then click the "Change..." button.
(replace account with the name or word that appears in front of the '@' symbol
, and replace mydomain.com with your domain name). Near the bottom click on "More Settings...".
Click on the "Outgoing Server" tab, place a check mark in the box for "My outgoing server (SMTP) requires authentication", and ensure the option "Use same settings as my incoming mail server" is selected. Click "OK".
Once all settings have been confirmed, click on the "Next" button at the bottom of the window, again click "Finish" in the next window.