SMTP-NO-STARTTLS
The mail server does not offer STARTTLS
What it means
Without STARTTLS every message arrives in clear text across the internet. Google and others now flag or downgrade unencrypted delivery.
How to fix it
- 1Enable STARTTLS in the MTA (Postfix: smtpd_tls_security_level = may) with a certificate from a public CA.
Re-check after the change
DNS changes can take up to the record's TTL to be seen; use Re-run on the result page to bypass our 10-minute cache.