Thought I'd post this here after much hair pulling frustration.
Have been trying to get Gmail MAIL settings working on my 931L for a few weeks, thought everything was perfect, triple checked all SMTP, username, SSL, searched everywhere for solutions.
All I could get when I tested the settings was 'Invalid Username/Password' for the test results, knowing full well all settings were correct.
After watching the Demo video linked from this forum and realising it could actually work, and it's not some DLINK troll joke run by office employees, I thought about it again and realised
My account has Google Authenticator on it
This was blocking my connection
Sure enough I switched to a secondary account and it worked straight away.
Not sure if this has been posted before but thought I might lay it out in case somebody else was having similar issues.