Please dont cross-post. I replied to you the first time you posted this at:
https://www.ubbdev.com/forums/ubbthreads.php/topics/323034/re-ubb-emails-not-sending.html#Post323034

What I wrote was
---------------------

Is this what you're looking for?
https://www.ubbcentral.com/forums/ubbthreads.php/topics/252563/google-apps-and-ubb-threads

the current settings should be simular to the following (update your website GSuite domain and password:

Code
    public $Host = 'smtp.gmail.com';
    public $Port = 587;
    public $SMTPSecure = 'tls';
    public $SMTPAutoTLS = true;
    public $SMTPAuth = true;
    public $Username = 'forum@EXAMPLE.com';
    public $Password = 'PASSWORD';

Also see attached screenshot of /forums/libs/phpmailer/class.phpmailer.php

[Linked Image from ubbdev.com]

Current developer of UBB.threads PHP Forum Software
Current Release: UBBT 7.7.5 // Preview: UBBT 8.0.0
isaac @ id242.com // my forum @ CelicaHobby.com