Apex domains cannot have CNAME records.
Question and response
Question
dig fanniemae.com. NS
Answer
fanniemae.com. 5 NS ns4.fanniemae.com.
fanniemae.com. 5 NS ns1.fanniemae.com.
fanniemae.com. 5 NS pdns111.ultradns.net.
fanniemae.com. 5 NS pdns111.ultradns.biz.
fanniemae.com. 5 NS ns2.fanniemae.com.
fanniemae.com. 5 NS ns5.fanniemae.com.
fanniemae.com. 5 NS pdns111.ultradns.com.
fanniemae.com. 5 NS pdns111.ultradns.org.
Authority
The response has no authority records.
Additional
ns1.fanniemae.com. 5 A 198.204.134.65
ns2.fanniemae.com. 5 A 198.204.142.65
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0