f-090.mailcomp.net has no CNAME records.
Question and response
Question
dig f-090.mailcomp.net. NS
Answer
The response has no answer records.
Authority
mailcomp.net. 256 SOA x.ns.joker.com. hostmaster.joker.com. 2024110768 14400 3600 1209600 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0