Why are TLS reports useful?
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But without TLS-RPT, you're flying blind on certificate and encryption problems. Senders simply bounce your mail silently. TLS-RPT fixes that by showing you exactly where the friction is.
What you catch early: A certificate that's about to expire. Your TLS-RPT report will spike with certificate-expired or certificate-not-trusted failures days or weeks before your cert actually expires. Fix it before it tangles with your MTA-STS policies that enforce encryption, not after. A STARTTLS negotiation that's broken. Maybe your server isn't advertising STARTTLS correctly, or you misconfigured cipher suites. The report tells you the IP of senders who failed, so you can test against them. A misconfigured MTA-STS policy that's too strict. You published an MTA-STS policy (which forces all connections to use TLS), but now legitimate senders can't reach you because of certificate mismatches. TLS-RPT shows you the damage in real time, so you can adjust your policy before enforcing it globally.
The pattern recognition matters, too. If you're seeing only one sending server fail with certificate-not-trusted, it's probably their old mail server. If all senders report it, your certificate chain is broken and you need to act now.
TLS-RPT gives you visibility into the quiet failures. Get started with setup and start collecting that data.
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