mx.cie.ac has no CNAME records.
Question and response
Question
dig mx.cie.ac. NS
Answer
The response has no answer records.
Authority
cie.ac. 186 SOA ns1.cie.ac. hostmaster.cie.ac. 2026012006 10800 3600 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0