mrtg.summitnix.net has no CNAME records.
Question and response
Question
dig mrtg.summitnix.net. NS
Answer
The response has no answer records.
Authority
summitnix.net. 10800 SOA dns1.summitnix.net. admin.summitnix.net. 2019120801 3600 3600 604800 10800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0