'''Port Number''': This is the email server SMTP port. This is normally 25 but can be different. For example the gmail server uses 465. This setting only applies if you are using your own email address to send notifications.
Trouble Shooting
Gmail can sometimes block access to external systems.
The solution is to create an application password, this video explains how.
http://www.youtube.com/watch?v=zMabEyrtPRg&t=2m13s