Error: a Gmail to Gmail email via an Infomaniak address forward, fails to reach destination

If you send an email from youraddress@gmail.com to address@domain.xyz (domain that we host) and that forwarding is set up for address@domain.xyz to youraddress@gmail.com, youraddress@gmail.com will never display your email, that it should have received.

Indeed, an email from Gmail to Gmail via the forwarding of an Infomaniak address causes a problem on Gmail's side, in the way it handles mail. These are its characteristics and explains why your message will never arrive (for in fact, as far as Gmail is concerned, it is already in the mail box, under sent items).