Apex domains cannot have CNAME records.
Question and response
Question
dig mcc-ixc.com. NS
Answer
mcc-ixc.com. 4 NS adns2.metrocomm.com.
mcc-ixc.com. 4 NS adns1.metrocomm.com.
Authority
The response has no authority records.
Additional
adns1.metrocomm.com. 4 A 192.35.202.145
adns2.metrocomm.com. 4 A 162.255.12.205
adns1.metrocomm.com. 4 AAAA 2607:5380:c001:9:0:0:0:3
adns2.metrocomm.com. 4 AAAA 2607:5380:c001:a:0:0:0:3
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0