Apex domains cannot have CNAME records.
Question and response
Question
dig tdatacenter.com. NS
Answer
tdatacenter.com. 4 NS esifw1.tsai.es.
tdatacenter.com. 4 NS esifw2.tsai.es.
Authority
The response has no authority records.
Additional
esifw1.tsai.es. 4 A 213.0.43.37
esifw2.tsai.es. 4 A 213.4.194.5
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0