MTA STS Lookup

Enforce: In this mode, failing the TLS means that the emails won’t be delivered (similar to the DMARC reject policy). However, you’ll still receive reports.
Testing: The messages that fail to pass the TLS won’t be blocked, but you’ll be able to gather data on them. Enable TLS-RPT to start getting the reports. (Acts much like the quarantine policy in DMARC, doesn’t it?).
Enforce: While the modes above are somewhat comparable to DMARC policies, this one is very distinct. The none policy in your MTA-STS file means fully disabling the policy.

Use this tool to check, lookup, and validate your MTA-STS record and policy and get configuration suggestions.

Enter a domain

The tool helps users validate MTA-STS configurations, identify issues, and improve email security. It ensures compliance with best practices, protecting against email interception. Organizations can use it to strengthen domain defenses, reduce risks, and maintain secure email communication.