mail1.jscnet.se has no CNAME records.
Question and response
Question
dig mail1.jscnet.se. NS
Answer
The response has no answer records.
Authority
jscnet.se. 10800 SOA ns1.jscnet.se. registry.jsc.nu. 1353331992 10800 3600 604800 38400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0