Apex domains cannot have CNAME records.
Question and response
Question
dig wpcloud.com. NS
Answer
wpcloud.com. 5 NS ns4.automattic.com.
wpcloud.com. 5 NS ns3.automattic.com.
wpcloud.com. 5 NS ns1.automattic.com.
wpcloud.com. 5 NS ns2.automattic.com.
Authority
The response has no authority records.
Additional
ns1.automattic.com. 5 A 198.181.116.5
ns2.automattic.com. 5 A 198.181.117.5
ns3.automattic.com. 5 A 192.0.74.5
ns4.automattic.com. 5 A 192.0.75.5
ns1.automattic.com. 5 AAAA 2a04:fa87:ffff:0:0:0:c6b5:7405
ns2.automattic.com. 5 AAAA 2a04:fa87:ffff:0:0:0:c6b5:7505
ns3.automattic.com. 5 AAAA 2620:115:c00f:0:0:0:c000:4a05
ns4.automattic.com. 5 AAAA 2620:115:c00f:0:0:0:c000:4b05
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0