Error: Mail service not enabled

If you see this 400 error for a Google account, it indicates that API calls to the mail service are being rejected.

Mail service not enabled

Cause

This error happens when the account has the Gmail service turned off in Google Workspace. This means the user has a valid Google account tied to that email address, but the underlying mailbox capability is not active. This can occur if the G Suite license for that user is not enabled, has expired, or the service was manually disabled by their administrator.

Resolution

The user must ask their Google Workspace administrator to:

1. Turn on the Gmail service for their specific user account in the Google Admin Console.
2. Verify the G Suite license for that user is current and includes the Gmail service.

3. Re-authenticate the Nylas grant after the Gmail service has been enabled to ensure access permissions are correctly refreshed. 

Note: If the email administrator has switched the email provider away from Google, the user must instead re-authenticate the Nylas grant with the new, active email provider.

Resources

Turn Gmail on or off for users