Apex domains cannot have CNAME records.
Question and response
Question
dig tpx.net. NS
Answer
tpx.net. 5 NS ns1.dsci-net.com.
tpx.net. 5 NS ns2.dsci-net.com.
Authority
The response has no authority records.
Additional
ns1.dsci-net.com. 5 A 66.81.135.51
ns2.dsci-net.com. 5 A 209.104.248.253
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0