Why doesn't forwarding to Gmail or (G Suite) work when I test it from Gmail (or G Suite)?
If you set up a forwarding email address that delivers messages to Gmail or an address handled by Google’s “G Suite” mail service, then test the forwarding by sending a message from that same address, the test won’t seem to work, even though we forward it properly. Google just won’t put the forwarded message into your Gmail “Inbox”.
Can you give me an example?
Let’s say you set up “email@example.com” to forward email to “firstname.lastname@example.org”.
If you send a test message from “email@example.com” to “firstname.lastname@example.org”, the message will be forwarded by our servers, but Gmail will discard the message.
This problem makes it look like the forwarding doesn’t work, even though mail sent from any other address to “email@example.com” would work properly.
If you want to test an address that forwards mail to a Gmail address, send the test message from any address except the final Gmail destination address.
Why does this problem happen?
Google does this intentionally. According to their help page:
Messages that you send to a mailing list, or to an email address that's automatically forwarding your mail to Gmail, will only appear in your Sent Mail.
We think this is a misguided policy (it causes a great deal of confusion), but it’s something they control, not us. It happens with any mail forwarded to Google, not just mail forwarded by our company.