28b2d55f.21.ik2.com has no CNAME records.
Question and response
Question
dig 28b2d55f.21.ik2.com. NS
Answer
The response has no answer records.
Authority
ik2.com. 16529 SOA ns1.ik2.com. dns.ik2.com. 2026021102 14400 3600 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0