c.nic.es has no CNAME records.
Question and response
Question
dig c.nic.es. NS
Answer
The response has no answer records.
Authority
nic.es. 7200 SOA ns1.nic.es. hostmaster.red.es. 2026020701 7200 1800 1209600 7200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0