Cant create new email domain

I get this error regarless what I “Errno 111”… I have full control of the mailserver on that ip address.
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Are there any logs that can revelive more information on whats wroing?

@tomasenskede check this ERROR: Message Incoming email account not correct

Please check this.

Not sure but, you cannot use an IP address in an email domain.

Please check the video reference: