Apex domains cannot have CNAME records.
Question and response
Question
dig ultradns2.org. NS
Answer
ultradns2.org. 2 NS pdns1.ultradns.net.
ultradns2.org. 2 NS pdns5.ultradns.info.
ultradns2.org. 2 NS ns61.ultradns2.com.
ultradns2.org. 2 NS pdns2.ultradns.net.
ultradns2.org. 2 NS ns61.ultradns2.org.
ultradns2.org. 2 NS pdns4.ultradns.org.
ultradns2.org. 2 NS pdns3.ultradns.org.
ultradns2.org. 2 NS pdns6.ultradns.co.uk.
Authority
The response has no authority records.
Additional
ns61.ultradns2.com. 2 A 204.74.104.61
ns61.ultradns2.org. 2 A 204.74.106.61
pdns1.ultradns.net. 2 A 204.74.108.1
pdns2.ultradns.net. 2 A 204.74.109.1
pdns3.ultradns.org. 2 A 199.7.68.1
pdns4.ultradns.org. 2 A 199.7.69.1
pdns5.ultradns.info. 2 A 204.74.114.1
pdns6.ultradns.co.uk. 2 A 204.74.115.1
ns61.ultradns2.com. 2 AAAA 2610:a1:313d:0:0:0:0:53
ns61.ultradns2.org. 2 AAAA 2610:a1:323d:0:0:0:0:53
pdns1.ultradns.net. 2 AAAA 2001:502:f3ff:0:0:0:0:1
pdns2.ultradns.net. 2 AAAA 2610:a1:1014:0:0:0:0:1
pdns3.ultradns.org. 2 AAAA 2610:a1:1015:0:0:0:0:1
pdns4.ultradns.org. 2 AAAA 2001:502:4612:0:0:0:0:1
pdns5.ultradns.info. 2 AAAA 2610:a1:1016:0:0:0:0:1
pdns6.ultradns.co.uk. 2 AAAA 2610:a1:1017:0:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0