Verify SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail) records propagation for your domain. It is 100% free to use. These DNS-based mechanisms validate your emails by confirming the identity of the sender, thus preventing potential spoofing threats. The SPF record validates the outgoing mail server, indicating that it is authorized to send emails on behalf of your domain. The DKIM record provides a digital signature in the headers of your emails, adding an extra layer of validation.