mxin.thrifty.net has no MX records.
Question and response
Question
dig mxin.thrifty.net. MX
Answer
The response has no answer records.
Authority
thrifty.net. 86400 SOA ns3.lsn.net. root.lsn.net. 2024010301 10800 60 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0