prot.questinspect.com has no MX records.
Question and response
Question
dig prot.questinspect.com. MX
Answer
The response has no answer records.
Authority
questinspect.com. 86400 SOA ns1.multacom.com. support.multacom.com. 2026020505 10800 3600 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0