Email Notifications (through Gravity Forms)

I’m not getting email notifications when a form is filled out with a specific email domain.

My client, FedEx, can fill out our form, and click submit….but we never receive notification. Through tests, any other domain I try as the “sender” works & we get notified.

Further, I’ve asked these same users to email me directly, and there is no problem.

Per Gravity Forms (plug-in), I’ve tried their “solutions” — checking theme & version conflicts, etc…….and haven’t figured this out.

Does WP filter email from some domains?

Thanks,
Jeremiah