dns1.jazzvisp.com has no CNAME records.
Question and response
Question
dig dns1.jazzvisp.com. NS
Answer
The response has no answer records.
Authority
jazzvisp.com. 10800 SOA dns1.jazzvisp.com. dnsmaster.jazzvisp.com. 2014021108 86400 7200 2592000 172800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0