Issues with spammers using DNS servers

Windows Server
1

Some of the emails got rejected in my company (we use exchange email server), because of the spammers using DNS servers to host their domain. Does anybody know anything about this, and why is this happening?

2

Hi @MylesBill,
I think this thread will do a lot of help to your issue

3

Hey there!
Check the information in this link
It shows why and how ti fix it
https://manuals.gfi.com/en/kerio/connect/content/server-configuration/mail-delivery-and-dns-records/essential-dns-records-for-mail-delivery-and-spam-protection-1223.html