kron.seanet.com has no CNAME records.
Question and response
Question
dig kron.seanet.com. NS
Answer
The response has no answer records.
Authority
seanet.com. 9607 SOA dns1.seanet.com. dns-admin.seanet.com. 2026021801 1800 900 3600000 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0