Users may report that their Voicemail to Email feature or other service(s) using email relay is no longer working on their UCX when they have configured GMAIL as their Remote SMTP service on the UCX.
Google recently made changes to their App Password settings. As a result, the UCX Remote SMTP functionality may fail due to the existing Username and Password credentials not being accepted. This can be quickly recovered by creating a new App Password on the GMail account and entering it into the UCX Remote SMTP settings.
There are two ways to verify that the Voicemail to Email failure is due to the GMAIL SMTP server not accepting the existing account credentials:
You can recover from this situation by creating a new Google App Password as described below and re-enter it into the UCX Remote SMTP settings. (For full details on th Google App Password process, refer to this Google Support document.)