mx00.mucix.net has no TXT records.
Question and response
Question
dig mx00.mucix.net. TXT
Answer
The response has no answer records.
Authority
mucix.net. 600 SOA dns0.noris.net. hostmaster.noris.net.mucix.net. 1772904423 86400 86400 2419200 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0