Steps to enable SMTP Authentication in Outlook 2016

Step 1: Go to the ‘File’ tab, Click on ‘Account Settings’.
Step 2: Select email account you need to update.
Step 3: Select the ‘Outgoing Server’ tab
Step 4: Tick ‘My outgoing server (SMTP) requires authentication’
Step 5: Select ‘Log on using’
Step 6: Enter the AuthSMTP username and password we supplied when you signed up
Step 7: Tick the ‘Remember password’ option
Step 8: Click ‘OK’