I have new information on this subject
After investigating about this, I realised that I can send the messages to the correct Queue, which is what matters at the end.
So I've created a new Exchange dedicated to Mailwizz and created a bind with a routing key to the final Queue.
So I'm now able to send the message to the final queue.
However a new problem appeared. I'm receiving this bounce:
[2017-08-24 16:48:06] message:error 1 <info@XXXX> <xxx@xxx.xx> [x.x.x.x] x.x.x.x] [] 550 5.7.1 [x.x.x.x 11] Our system has detected that this message is not RFC 5322 compliant: 'From' header is missing. To reduce the amount of spam sent to Gmail, this message has been blocked. Please visit
https://support.google.com/mail/?p=RfcMessageNonCompliant and review RFC 5322 specifications for more information. h6si3673137wrh.246 - gsmtp
I tried to send the DS validation email to an email other than gmail and in fact I received it, but empty:
(...)
From:
xxx@xxx.xx
X-Envelope-From: <xxx@xxx.xx>
Received: from xxx.xx (xxx.xx [x.x.x.x) by mxa.mailgun.org with ESMTP id 599f040f.7fcff43cf470-smtp-in-n01; Thu, 24 Aug 2017 16:51:27 -0000 (UTC)
message-id: <2bd01604-6765-49fd@bbed-67c058b442fe>
[ENDS HERE]
Any idea what could be this?
* It's probably my mistake somewhere