We recommend that you register at least two security keys for each service you enable two-factor authentication with. Once you lose a security key, log in using your backup key or another backup option (i.e. Google Authenticator or backup codes). After accessing the security settings on your account, remove the lost security key from from the list of security keys. For more information, see our Knowledge Base article.

in Frequently Asked QuestionsUniversal 2nd Factor (U2F)