mail.startuplabs.cc has no CNAME records.
Question and response
Question
dig mail.startuplabs.cc. NS
Answer
The response has no answer records.
Authority
startuplabs.cc. 266 SOA ajay.ns.cloudflare.com. dns.cloudflare.com. 2396342001 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0