b.ns.as137341.net has no MX records.
Question and response
Question
dig b.ns.as137341.net. MX
Answer
The response has no answer records.
Authority
as137341.net. 3600 SOA a.ns.as137341.net. contact.as137341.net. 2020082401 7200 1800 1209600 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0