Apex domains cannot have CNAME records.
Question and response
Question
dig e.firstmarkservices.com. NS
Answer
e.firstmarkservices.com. 5 NS ns1.acoustic-adm.com.
e.firstmarkservices.com. 5 NS ns2.acoustic-adm.com.
e.firstmarkservices.com. 5 NS ns3.acoustic-adm.com.
e.firstmarkservices.com. 5 NS ns4.acoustic-adm.com.
Authority
The response has no authority records.
Additional
ns2.acoustic-adm.com. 2 A 205.251.198.78
ns3.acoustic-adm.com. 2 A 205.251.194.123
ns4.acoustic-adm.com. 2 A 205.251.192.237
ns2.acoustic-adm.com. 2 AAAA 2600:9000:5306:4e00:0:0:0:1
ns3.acoustic-adm.com. 2 AAAA 2600:9000:5302:7b00:0:0:0:1
ns4.acoustic-adm.com. 2 AAAA 2600:9000:5300:ed00:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0