Sending to [email protected]

When trying the test email tool, sending to [email protected] works, but not when using [email protected] directly.

After checking with Google’s support, they say that it has to do with internal VS external MX lookup. Here is what the support said:

The address which you used for the last test ([email protected]) is a direct no MX lookup address – which is a temporary solution – to resolve the situation you will need to check the settings of the web form – and to set it to perform external lookups

Is there someway to resolve this?

Regards,
Phet