Single Domain Not Allowing User Registration

[HGMNinja]

Hi, I have a vps with Mailwizz installed, and another cps with a mail server installed. (iRedMail).
The domain at iRedMail is: mail.redmail.net
Now mailwizz will allow a user to register for a list, through a mailwizz form, using a gmail or other domain but the iRedMail server domain emails are not accepted and MailWizz giveds the error:

• We are sorry, but we cannot deliver the confirmation email right now!

Over the past few week mail servers etc, have become completely confusing to me. So I can only presume that my iRedMail server is rejecting... its own domain? ie, me@redmail.net

Does this seem to be the case or is it occuring on the MailWizz side?

I have the mail.redmail.net setup as a Delivery Server in MailWizz admin. See Image below for settings.

Any ideas of where I should start looking. Frankly, and this is strange... the iredmail server isnt giving much of a clue. Except this:

connect from vmi123456.contaboserver.net[197.197.197.197]
Sep 14 23:06:02 mail postfix/submission/smtpd[460791]: Anonymous TLS connection established from vmi123456.contaboserver.net[197.197.197.197]: TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)
Sep 14 23:06:03 mail postfix/submission/smtpd[460791]: NOQUEUE: reject: RCPT from vmi123456.contaboserver.net[197.197.197.197]: 554 5.3.1 <mail@redmail.com>: Recipient address rejected: Policy rejection due to null sender; from=<> to=<mail@redmail.com> proto=ESMTP helo=<localhost.localdomain>
Sep 14 23:06:03 mail postfix/submission/smtpd[460791]: using backwards-compatible default setting smtpd_relay_before_recipient_restrictions=no to reject recipient "mail@redmail.com" from client "vmi123456.contaboserver.net[197.197.197.197]"

So based on the error above, is there a way to change the "nul sender" part on the MailWizz delivery Server side? Wold changing the Force Sender setting achieve this? Or must the IP be whitelisted somehow in iRedMail server side of things?

Many thanks for any guidance on this. Much appreciated.

 

[twisted1919]

TBH this is more a questions for the iredmail forums than here, it seems its related to how iredmail treats its own emails.
I don't know why that from is empty/null, that's interesting, but as far as MailWizz goes, we for sure set that.

 

[HGMNinja]

TBH this is more a questions for the iredmail forums than here, it seems its related to how iredmail treats its own emails.
I don't know why that from is empty/null, that's interesting, but as far as MailWizz goes, we for sure set that.

Thank, I appreciate the pointer. I had that issue before and it was a simple fix - as suggested, just adding the IP address to... I think Postfix, but Like I say, I no longer have that file. Or at least havent been able to find it as yet. Thanks again. At least I know where to look.