Outgoing server : "smtp.gmail.com"
Server port : 465
Connection encryption : SSL
Authentication : Plain Password
Make sure you click the "Ok" button after you change the port to 465
Also note if you have the 2-step verification setup on your gmail account then you will need an app password that will bypass the 2-step verification and this password will be used in place of your normal account password.
See this link to create an app-password for your gmail account : Sign in using App Passwords - Accounts Help
Thank you for your help. The 2-step verification was the problem.