Apex domains cannot have CNAME records.
Question and response
Question
dig apps.gcds.disa.mil. NS
Answer
apps.gcds.disa.mil. 5 NS utindo02.csd.disa.mil.
apps.gcds.disa.mil. 5 NS guv10m01.csd.disa.mil.
apps.gcds.disa.mil. 5 NS sdns3.csd.disa.mil.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0