Apex domains cannot have CNAME records.
Question and response
Question
dig psg.com. NS
Answer
psg.com. 5 NS rip.psg.com.
psg.com. 5 NS ns1.rg.net.
psg.com. 5 NS psg.com.
psg.com. 5 NS nlns.globnix.net.
Authority
The response has no authority records.
Additional
ns1.rg.net. 5 A 46.224.94.61
psg.com. 5 A 147.28.0.62
rip.psg.com. 5 A 147.28.0.39
nlns.globnix.net. 5 A 94.142.241.91
ns1.rg.net. 5 AAAA 2a01:4f8:1c1a:5360:0:0:0:1
psg.com. 5 AAAA 2001:418:1:0:0:0:0:62
rip.psg.com. 5 AAAA 2001:418:1:0:0:0:0:39
nlns.globnix.net. 5 AAAA 2a02:898:31:0:0:0:53:0
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0