Currently, our Email Threat Protection solution requires a special setup in order to ensure email delivery is kept at a consistent rate for G Suite clients. In the past, we have had issues delivering to G Suite MX records. Google’s environment thinks we are bulk mailing and grey lists our servers, resulting in delays for G Suite customers. In order to avoid this from happening, we suggest creating a CNAME DNS record that points to the Google MX records. The extra DNS resolution avoids any delivery issues we have seen in the past when delivering to G Suite MX records. We create CNAME records because if Google ever changes delivery locations, the CNAME record will automatically resolve those changes. Once the CNAME is created, we will use that record as the Email Threat Protection delivery location.
Here is an example of how it should look when you are creating the record. This is from GoDaddy’s site.
Host: Can be whatever the client prefers, most use “Delivery” (This does not matter, as long as it's not going to interfere with any other CNAME records, such as the Autodiscover record). This will make the record “Delivery.domain.com” that will resolve to “ASPMX.L.GOOGLE.COM”.
**** Verify that you have put in the correct G Suite MX record. This example is from their current configuration, but it can change. ****
Once that is created, allow some time for propagation. Once time has past, you can verify to ensure the record is correct. If you do a CNAME search for that record “delivery.domain.com” it should resolve to the G Suite MX records: