MX points to a CNAME
Check id: mx.points_to_cname · fix effort: low
What it means
Your mail server entry points at an alias instead of a real hostname. Technically invalid and a source of odd delivery issues.
The technical detail
RFC 2181 10.3: MX targets must not be CNAMEs. Many MTAs tolerate it, some don't.
How to fix it
- Point the MX directly at the A/AAAA hostname the alias resolves to.
Does your domain have this problem?
Run a free scan, takes about ten seconds.