czmailserver.cloud4c.com has no CNAME records.
Question and response
Question
dig czmailserver.cloud4c.com. NS
Answer
The response has no answer records.
Authority
cloud4c.com. 27 SOA ns20.ctrls.in. hostmaster.ctrls.in. 2023020110 28800 7200 1209600 100
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0