Bringing this back up after an experience I had yesterday.
Upgraded a client to 2014.3. They want to activate Paperless emailing, and are a Google Apps business user. So their email addresses are not
xxx@gmail.com.
I configured Company Maintenance per the Sage KB (email address = smtp.gmail.com, port 587, TLS/STARTTLS encryption). Email failed (I didn't capture the exact message, but it was not happy with the username/password. Client's IT confirmed the user/pw combination (we even had 2 different sets of fingers configure the pw).
Turns out that to get it working, changing the following settings resulted in successful emailing:
address = smtp-relay.gmail.com; user id and password removed.
Apparently, this tells the Gmail server to accept messages from the IP address of the server.
In case anyone runs into this . . .