An mx mechanism points at a name with no mail exchangers
ATTENTIONWhat it means
example.net publishes no MX records, so this mechanism authorises nothing and spends one of the two void lookups a record is allowed.
How to fix it
Publish MX records for example.net, or remove the mechanism.
Check your own domain
This page describes the condition. To find out whether your domain has it, run the SPF test or the full checkup, which examines every record at once.
Understand it properly
This page covers one condition. For the whole picture, What is SPF, and the ten-lookup limit, or start at the Health Library.
Where this comes from
We judge this against RFC 7208 section 5.4. Every finding on this site cites the specification behind it so you can check the work rather than take our word for it.
Other SPF conditions
SPF_MX_TARGET_VOID
Every fix on this site is yours to implement. If you would rather someone did it, I take this work directly.