GMail: Token has been expired or revoked

We are experiencing this error about once a week and several people are now reporting this problem with no relief in sight.

Mailer: Gmail
{
“error”: “invalid_grant”,
“error_description”: “Token has been expired or revoked.”
}
Please re-grant Google app permissions!
Go to WP Mail SMTP plugin settings page. Click the “Remove Connection” button.
Then click the “Allow plugin to send emails using your Google account” button and re-enable access.

During the process of establishing (or reestablishing) the SMPT service with GMail, I get two warnings of concern when I set up the connection:
(1) “Google hasn’t verified this app” with “You’ve been given access to an app that’s currently being tested.”
I hit continue.

(2) I am to grant access to wpmailsmtp.com to:
Read, compose, send, and permanently delete all your email from Gmail
Why does an SMPT service need to read and/or delete any mail on my gmail account if I am just using this as a sending service for a “Contact Me” form?

I click through, I establish the SMPT service and it works for a few days, and then fails (back to top)…

Any suggestions?

William

(https://www.ads-software.com/support/topic/token-has-been-expired-or-revoked-8/)

The page I need help with: [log in to see the link]