mx.andorratelecom.ad has no NS records.
NS records for this zone are defined at andorratelecom.ad.
NS records for this zone are defined at andorratelecom.ad.
Question and response
Question
dig mx.andorratelecom.ad. NS
Answer
The response has no answer records.
Authority
andorratelecom.ad. 900 SOA ns1.andorratelecom.ad. ns.andorratelecom.ad. 266 10800 3600 2419200 900
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0