MTA-STS/TLS-RPT Record Lookup

Mail Transfer Agent-Strict Transport Security (MTA-STS) is a protocol that makes it mandatory for any outgoing email from the domain to be TLS encrypted before being delivered to the recipient. Transport Layer Security Reporting is a protocol used alongside MTA-STS that enables the domain owner to receive reports with information on emails that failed to be delivered because the receiving server didn’t support TLS encryption.