Google SMTP OAuth2 Authentication - Using Client Gmail Accounts

We have PHP Pear Mail working perfect with SMTP From our server using NON-GMAIL addresses as the sender. However, when we use a gmail account as the sender, it fails to authenticate no matter what ports or authentication we try. We do NOT want to require users to 'disable 2 step verification'. If you know this problem and know how to solve it, I want to hire you. Must have experience with Google Authentication using SMTP We have created a php file for you. Code is already created using PHP Pear Mail. We will provide both FTP and SSH access to the folder which contains needed file. This must work on OUR server, not just your test server. Perhaps this is a problem because of setup inside Google's world. We do not know. That's why we are hiring you. An example of code we have created can be seen here: [login to view URL] Please help us solve Google OAuth2 problems Thank you. Sincerely, Jay CompuMatter