A mail server hostname doesn't resolve

Check id: mx.unresolvable · fix effort: medium

What it means

One of your listed mail servers doesn't exist in DNS. Mail routed to it bounces or gets delayed.

The technical detail

An MX target has no A or AAAA record. If it's the only MX, all inbound mail fails.

How to fix it

  1. Fix or remove the dead MX record at your DNS host.
  2. Verify remaining MX hosts resolve and accept connections on port 25.

Does your domain have this problem?

Run a free scan, takes about ten seconds.