mx.cltel.net has no CNAME records.
Question and response
Question
dig mx.cltel.net. NS
Answer
The response has no answer records.
Authority
cltel.net. 420 SOA ns1.ispn.net. servers.ispn.net. 2025110702 3600 600 1209600 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0