mx01.iso.afrinic.net has no TXT records.
Question and response
Question
dig mx01.iso.afrinic.net. TXT
Answer
The response has no answer records.
Authority
iso.afrinic.net. 1800 SOA ns1.afrinic.net. dnsmasters.afrinic.net. 2026022000 1800 1800 1814400 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0