smtp.nordext.net has no MX records.
Question and response
Question
dig smtp01.nordext.net. MX
Answer
The response has no answer records.
Authority
nordext.net. 86400 SOA dns1.inasset.net. domains.inasset.it. 2026010501 3600 1800 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0