I have a catch all email forwarding on my domain name, which works if I send a regular email to my domain name.
However, if I use a rapid weaver contact form, emails to anything@ my domain never arrive at the forward address (a gmail account). I don’t see any error messages and the form indicates it has sent out the email. I tried it with and without the php check box. I have tried the form with http and https. The theme, if it matters, is Delta.
If I change the email address on the contact form to the gmail account, the contact form works correctly.
Most other posts I see here discuss the problem when the hosting server requires the same domain name on the email. This problem is the exact opposite. It’s a failure if the domain and email address domain name match.