ns2.cetsi.eu has no CNAME records.
Question and response
Question
dig ns2.cetsi.eu. NS
Answer
The response has no answer records.
Authority
cetsi.eu. 6224 SOA ns1.cetsi.fr. postmaster.cetsi.fr. 2014636924 21600 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0