Test connection for the Incoming Mail Handler is failing with an error for re-authorization

Summary

When testing the connection of an Incoming Mail Handler, an error is displayed indicating the need for re-authorization.

Environment

Cloud

Cause

The Gmail account used for setup must possess the "Read, compose, and send emails from your Gmail account" permission.

Solution

Delete the current mail server, ensure to enable (check mark) the permission of "Read, Compose, and send emails" from your Gmail account and then set up the mail server again.