alertsys.hringdu.is has no CNAME records.
Question and response
Question
dig alertsys.hringdu.is. NS
Answer
The response has no answer records.
Authority
hringdu.is. 133 SOA ns1.hringdu.is. hostmaster.hringdu.is. 1771509230 86400 7200 3600000 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0