Apex domains cannot have CNAME records.
Question and response
Question
dig frontieronline.com. NS
Answer
frontieronline.com. 5 NS auth.lkvl.mn.frontiernet.net.
frontieronline.com. 5 NS auth.roch.ny.frontiernet.net.
frontieronline.com. 5 NS auth.dlls.pa.frontiernet.net.
Authority
The response has no authority records.
Additional
auth.roch.ny.frontiernet.net. 5 A 50.48.212.201
auth.roch.ny.frontiernet.net. 5 AAAA 2001:1960:20:1030:400:0:0:201
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0