Google Apps

1. Login to Google Apps for Work Admin Panel.
2. Go to “Apps” settings: Manage Apps and their settings.
3. Select “Google Workspace“: Gmail, Calendar, Drive, & more.

1. Select “Gmail“.

1. Scroll to the bottom and click “Advanced Settings“. (direct link)
2. Uncheck option “Allow per-user outbound gateways” and Save.
3. Wait for 1 hour.
4. Check (reactivate) “Allow per-user outbound gateways” option and Save.
5. Wait for 1 hour.
6. Try to set “Send Mail As” feature in your Google Apps Gmail Settings again.

If it’s a success you will see SMPT outgoing setting after you submit the “Send mail as” email address and no longer see “Functionality not Enabled” message.

update: 23/07/2021