Apex domains cannot have CNAME records.
Question and response
Question
dig static.telenet.be. NS
Answer
static.telenet.be. 5 NS ns.telenet-ops.be.
static.telenet.be. 5 NS ns2.telenet-ops.be.
Authority
The response has no authority records.
Additional
ns.telenet-ops.be. 5 A 195.130.132.22
ns2.telenet-ops.be. 5 A 195.130.136.242
ns.telenet-ops.be. 5 AAAA 2a02:1800:100:5:0:0:0:1
ns2.telenet-ops.be. 5 AAAA 2a02:1800:100:5:0:0:0:2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0