TLS Certificate Check
Validate mail certificate hostname, chain and expiration.
What this test checks
Certificate hostname, issuer, validity dates and TLS negotiation evidence.
Why this matters
An expired or mismatched certificate can prevent authenticated encrypted delivery.
How to fix common problems
Renew certificates before expiration and include every served mail hostname.
FAQ
Is this a website certificate test?
This page focuses on certificates presented by SMTP servers after STARTTLS.