mx.andorratelecom.ad has no CNAME records.
Question and response
Question
dig mx.andorratelecom.ad. NS
Answer
The response has no answer records.
Authority
andorratelecom.ad. 427 SOA ns1.andorratelecom.ad. ns.andorratelecom.ad. 266 10800 3600 2419200 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0