Apex domains cannot have CNAME records.
Apple
Domain verification
apple-domain-verification=0j2sFvSMma6WmN4K
Atlassian
Domain verification
atlassian-domain-verification=KA0gfs8HwZTbVtC0dYHq8xj4LzbCfMLL3FIH0axPqe+YjI4lXMo7/a3Lk7YSW2Ns
Cisco CI
Domain verification
cisco-ci-domain-verification=3b206d2cdf5ac8b1ec7a4dd22c544cbbb646ed3601682ea6e90ec1971c9a7cbc
Facebook
Domain verification
facebook-domain-verification=ftiwx7p5tmwfz4yu78p4whnt5x3qvq
Google
Domain verification
google-site-verification=5Urj3dupkLD8pn4SIg9SFxPhwbOsPsndmXHhabzHRVY
Google
Domain verification
google-site-verification=do-Ij3Ewwn7C00y5c1IgOGT2qpTEQxM6ClwVbSK6obY
Google
Domain verification
google-site-verification=GS-4jMDKjSMN6h5xKl-HQaHjSl3KaKd_RT_mh_nMKGs
Google
Domain verification
google-site-verification=JBjVehDvia_RgtDmamQP-SMZqwYITrQu0gNMlhjXku8
Google
Domain verification
google-site-verification=O6s2ZjJ0MEXX3ndxDRa_ZYVewD9yCa3716t9gEmRVno
Google
Domain verification
google-site-verification=q0DJxG88VKkAWFQKZY3EOHJFdkjmvz7QTaI5j9OLPSQ
Google
Domain verification
google-site-verification=sKATxndsVTB2Sirk_FCDl6BNLOYNOInKk7SuNzqoRmM
Google
Domain verification
google-site-verification=WUnkwYnXpq4umHvaU3gtQAljD3HPwu3CWRAtPJyStFo
Microsoft
Domain verification
MS=ms15991931
Microsoft
Domain verification
MS=ms23099516
Pardot
Domain verification
pardot_270872_*=f86280b3a9cb2153f6b806bd3d925f44aa4ffd8208e540b5d1018356307bbde4