dsr.g2server.com has no CNAME records.
Question and response
Question
dig dsr.g2server.com. NS
Answer
The response has no answer records.
Authority
g2server.com. 87 SOA ns1.geetoo.com. hostmaster.geetoo.com. 20190427 1200 600 1209600 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0