Can send but not receive, but do receive some error messages

Hello,
I just got mailcow running recent in Debian and I have no problems at all sending mail, it doesn’t even end up in spam folders of everyone I have sent to. I can not receive any emails, however, but if I do send an email like so (test@123.456.789.0, in other words, with my IP address instead of my domain) I will, about instantly, receive an error message saying the mail server rejected the email due to it being syntax/no one with that address found/etc. I can also get a similar situation if I misspell the word before the @, but when I send it correctly, I receive no error and it does not appear in the inbox either.

My domain is through cloudflare, the mail server is self hosted. I have the “mail.example.com” as dns only, as are any related to the email system, as I read it could cause issues, but whether or not the proxy is on or off, I get the same results.

The mail cow system is running on a Debian VM on unraid, which also has nginx proxy manger and a few other things running on there if that matters at all.

Where do I go from here?