nsr1.bticglobal.net has no MX records.
Question and response
Question
dig nsr1.bticglobal.net. MX
Answer
The response has no answer records.
Authority
bticglobal.net. 7200 SOA ns1.bticglobal.net. hostmaster.eu.bt.net. 2018093330 28800 7200 1209600 7200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0