Apex domains cannot have CNAME records.
Question and response
Question
dig mxhost.ro. NS
Answer
mxhost.ro. 5 NS tani.ns.cloudflare.com.
mxhost.ro. 5 NS norman.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
tani.ns.cloudflare.com. 5 A 108.162.192.224
tani.ns.cloudflare.com. 5 A 172.64.32.224
tani.ns.cloudflare.com. 5 A 173.245.58.224
norman.ns.cloudflare.com. 5 A 108.162.193.217
norman.ns.cloudflare.com. 5 A 172.64.33.217
norman.ns.cloudflare.com. 5 A 173.245.59.217
tani.ns.cloudflare.com. 5 AAAA 2606:4700:50:0:0:0:adf5:3ae0
tani.ns.cloudflare.com. 5 AAAA 2803:f800:50:0:0:0:6ca2:c0e0
tani.ns.cloudflare.com. 5 AAAA 2a06:98c1:50:0:0:0:ac40:20e0
norman.ns.cloudflare.com. 5 AAAA 2606:4700:58:0:0:0:adf5:3bd9
norman.ns.cloudflare.com. 5 AAAA 2803:f800:50:0:0:0:6ca2:c1d9
norman.ns.cloudflare.com. 5 AAAA 2a06:98c1:50:0:0:0:ac40:21d9
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0