imap.casjaydns.com has no CNAME records.
Question and response
Question
dig imap.casjaydns.com. NS
Answer
The response has no answer records.
Authority
casjaydns.com. 4754 SOA dns.casjaydns.com. dns-admin.casjaydns.com. 2026010368 10800 3600 1209600 38400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0