Rspam says MX Invalid

[lfirewall1243]

Hello,

i am having some Mails over Postfix and Rspam which get blocked, Rspam says "MX_INVALID (8)". But when I get the senders Domain and enter it on a page like "mxtoolbox.com" the page shows that the Domain has an valid MX Record.

Where is Rspam checking the MX Records? Or does it use the OPNsense configured DNS Server to check it?

[mimugmail]

It should use 127.0.0.1 if not otherwise changed

[lfirewall1243]

It should use 127.0.0.1 if not otherwise changed

Okay
i see that it is just happening when the MX goes to a "Hetzner" Domain/IP-Adress