ns6.kasserver.com has no CNAME records.
Question and response
Question
dig ns6.kasserver.com. NS
Answer
The response has no answer records.
Authority
kasserver.com. 594 SOA ns5.kasserver.com. hostmaster.kasserver.com. 2602250420 28800 7200 1209600 7200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0