SMTP-OLD-TLS
Mail server negotiates TLS 1.0 or 1.1
What it means
These versions are deprecated and refused by modern senders, which fall back to plain text or fail.
How to fix it
- 1Restrict the MTA to TLS 1.2 and 1.3.
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.