mailimap.fcomet.com has no CNAME records.
Question and response
Question
dig mailimap.fcomet.com. NS
Answer
The response has no answer records.
Authority
fcomet.com. 461 SOA alex.ns.cloudflare.com. dns.cloudflare.com. 2396408412 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0