dns.r-rooter.com has no CNAME records.
Question and response
Question
dig dns.r-rooter.com. NS
Answer
The response has no answer records.
Authority
r-rooter.com. 1029 SOA ns-443.awsdns-55.com. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0