Apex domains cannot have CNAME records.
Question and response
Question
dig inxserver.com. NS
Answer
inxserver.com. 1 NS ns4.inxmail.de.
inxserver.com. 1 NS ns1.dmz.inxmail.de.
Authority
The response has no authority records.
Additional
ns1.dmz.inxmail.de. 1 A 213.164.80.152
ns4.inxmail.de. 1 A 194.182.171.125
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0