ns76.irondns.net has no MX records.
Question and response
Question
dig ns76.irondns.net. MX
Answer
The response has no answer records.
Authority
irondns.net. 86400 SOA anycast30.irondns.net. dnsmaster.knipp.de. 2023090502 14400 3600 2419200 300
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0