Apex domains cannot have CNAME records.
Facebook
Domain verification
facebook-domain-verification=5q00m2b9mac7n95ota642ojbbf5xd4
Google
Domain verification
google-site-verification=x7Latm-0ddETzg1hr4mShl1z-SkwVBBJDXA6e2FVeIs
Google
Domain verification
google-site-verification=yiBCQc_j8S4Ju-0UgLLcdP4z68B1bBKo0T5GGzMTogc
Microsoft
Domain verification
MS=ms40044671
4T6-3H5-8P5
9454B7F789
cn0h8dl8shm2mhg3smsrjlr4ul
ebptvme0v3cr5b9ortvnhr0puq
ec0e6gt5bimv093q36gl1ksl1i
emkrsjagg4m00499f8rqq1o37b
F76FB71816
hqquvm72mppifkc8qk40bibpof
hudbtqm5fo3tijoeefp5olfbd4
q858df72dk4oq5lqdshqa9ti59
qdres0fgfnpefsafiim32jnesm
edna.ns.cloudflare.com
Cloudflare
lou.ns.cloudflare.com
Cloudflare
Zone apex
Start of authority
Email
Serial
2397040722
Refresh
2h 46m 40s
Retry
40m
Expire
7d
Negative cache TTL
30m