Apex domains cannot have CNAME records.
Question and response
Question
dig sol.net. NS
Answer
sol.net. 5 NS dns1.sol.net.
sol.net. 5 NS dnsz.sol.net.
sol.net. 5 NS dnsy.sol.net.
sol.net. 5 NS dnsw.sol.net.
sol.net. 5 NS dns4.sol.net.
sol.net. 5 NS dns3.sol.net.
sol.net. 5 NS dnsx.sol.net.
sol.net. 5 NS dns2.sol.net.
Authority
The response has no authority records.
Additional
dns1.sol.net. 5 A 206.55.64.64
dns2.sol.net. 5 A 206.55.64.65
dns3.sol.net. 5 A 206.55.64.66
dns4.sol.net. 5 A 206.55.64.67
dnsw.sol.net. 5 A 206.55.64.64
dnsx.sol.net. 5 A 206.55.64.64
dnsy.sol.net. 5 A 206.55.64.64
dnsz.sol.net. 5 A 206.55.64.64
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0