mx.dka.mailcore.net has no TXT records.
Question and response
Question
dig mx.dka.mailcore.net. TXT
Answer
The response has no answer records.
Authority
mailcore.net. 3600 SOA ns21.cloudns.net. postmaster.mailcore.com. 2026022502 7200 1800 1209600 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0