Error Message

My client set up their WP SMTP to forward emails from Gmail to a Yahoo email. As far as I can tell, the information they’ve entered for the settings is correct, but they keep having failed emails. In the error log, they keep getting messages that say:

“Mailer: Gmail
invalid_client
Please make sure your Google Client ID and Secret in the plugin settings are valid. Save the settings and try the Authorization again.”

We also got a message with error code 401 when UpdraftPlus tried to send an email backup:

Heads up! The last email your site attempted to send was unsuccessful.

Email Source: UpdraftPlus – Backup/Restore Mailer: Google / Gmail { “error”: { “code”: 401, “message”: “Request is missing required authentication credential. Expected OAuth 2 access token, login cookie or other valid authentication credential. See https://developers.google.com/identity/sign-in/web/devconsole-project.”, “errors”: [ { “message”: “Login Required.”, “domain”: “global”, “reason”: “required”, “location”: “Authorization”, “locationType”: “header” } ], “status”: “UNAUTHENTICATED”, “details”: [ { “@type”: “type.googleapis.com/google.rpc.ErrorInfo”, “reason”: “CREDENTIALS_MISSING”, “domain”: “googleapis.com”, “metadata”: { “service”: “gmail.googleapis.com”, “method”: “caribou.api.proto.MailboxService.SendMessage” } } ] } }

When we try to use the “Allow plugin to send emails using your Google account” button, we get a message that says:

“Access blocked: Authorization Error”

“Client missing a project id”

“Error 401: invalid_client”

Can you help me troubleshoot this issue?

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