mx.generic-isp.com has no TXT records.
Question and response
Question
dig mx.generic-isp.com. TXT
Answer
The response has no answer records.
Authority
generic-isp.com. 1800 SOA leia.ns.cloudflare.com. dns.cloudflare.com. 2396601730 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0