Apex domains cannot have CNAME records.
Facebook
Domain verification
facebook-domain-verification=lj771nwx7rhia7m6gcjn97rha9nxba
GlobalSign
Domain verification
globalsign-domain-verification=0E1F7BE140E000115DED76D5BC14F6F7
GlobalSign
Domain verification
globalsign-domain-verification=2D6A92FF9CF6923E9EF351B6C0A5439F
GlobalSign
Domain verification
globalsign-domain-verification=3CDDEAA0708C05E1DBA67EE4A7916A7F
Google
Domain verification
google-site-verification=9dX5sFlddz5tDPYn6btUwrbjN0rb7GQVoQbZSQum2wI
Google
Domain verification
google-site-verification=Q9XrEi4iBBKuW31t7y9bWopYRaNs9w_c_eky-OJgiE0
Microsoft
Domain verification
MS=ms24815992
Zone apex
Start of authority
Email
Serial
5
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1h
Retry
10m
Expire
7d
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1h