ns1.telefonica-data.com has no CNAME records.
Question and response
Question
dig ns1.telefonica-data.com. NS
Answer
The response has no answer records.
Authority
telefonica-data.com. 300 SOA nsjc8hos01.telefonica-data.com. dnsadmin.tsai.es. 52 300 300 300 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0