Apex domains cannot have CNAME records.
Question and response
Question
dig dreamhost.com. NS
Answer
dreamhost.com. 4 NS ns1.dreamhost.com.
dreamhost.com. 4 NS ns2.dreamhost.com.
dreamhost.com. 4 NS ns3.dreamhost.com.
Authority
The response has no authority records.
Additional
ns1.dreamhost.com. 4 A 162.159.26.14
ns2.dreamhost.com. 4 A 162.159.26.81
ns3.dreamhost.com. 4 A 162.159.27.84
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0