Apex domains cannot have CNAME records.
Question and response
Question
dig ims.telia.com. NS
Answer
ims.telia.com. 3 NS dns49.de.telia.net.
ims.telia.com. 3 NS dns2.telia.com.
ims.telia.com. 3 NS dns1.telia.com.
Authority
The response has no authority records.
Additional
dns1.telia.com. 3 A 81.228.11.67
dns2.telia.com. 3 A 81.228.10.67
dns49.de.telia.net. 3 A 213.248.77.82
dns1.telia.com. 1 AAAA 2001:2040:c001:101:0:0:0:5
dns2.telia.com. 1 AAAA 2001:2040:c001:401:0:0:0:6
dns49.de.telia.net. 3 AAAA 2001:2030:c000:5:0:0:0:4
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0