Apex domains cannot have CNAME records.
Question and response
Question
dig f5cloudservices.com. NS
Answer
f5cloudservices.com. 2 NS ns1.f5clouddns.com.
f5cloudservices.com. 2 NS ns2.f5clouddns.com.
f5cloudservices.com. 2 NS ns3.f5cloudservices.com.
f5cloudservices.com. 2 NS ns2.f5cloudservices.com.
f5cloudservices.com. 2 NS ns1.f5cloudservices.com.
f5cloudservices.com. 2 NS ns4.f5cloudservices.com.
Authority
The response has no authority records.
Additional
ns1.f5cloudservices.com. 2 A 107.162.234.197
ns2.f5cloudservices.com. 2 A 107.162.176.221
ns3.f5cloudservices.com. 2 A 107.162.197.131
ns4.f5cloudservices.com. 2 A 107.162.197.132
ns1.f5cloudservices.com. 2 AAAA 2604:e180:1071:0:0:0:3:1
ns2.f5cloudservices.com. 2 AAAA 2604:e180:1071:0:0:ffff:6ba2:b0dd
ns3.f5cloudservices.com. 2 AAAA 2604:e180:1071:0:0:ffff:6ba2:c583
ns4.f5cloudservices.com. 2 AAAA 2604:e180:1071:0:0:ffff:6ba2:c584
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0