If you added the CNAME record correctly and still not verified then I would suggest to check if the record is able to resolve or not. To check run a dig and see the response. If there is no response then it might be the case where you have added to the wrong hosted zone (meaning you might have multiple hosted zones).
Check your hosted zone NS server records where you have added the CNAME record are matching to the below set or not.
%dig NS domainname.com
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