To get in touch with our support team, open a support ticket here. *OpenPGP and PIV are less-commonly used than OTP, U2F, FIDO2, and OATHįor other YubiKeys/Security Keys, please the device page for the specific model of key in our KB's Devices section. *OpenPGP - the YubiKey 5's OpenPGP application can hold up to three OpenPGP private keys, one for encryption, one for signing, and one for authentication.*PIV - the YubiKey 5's PIV (smart card) application has 24 slots, each of which can hold one certificate and its corresponding private key (click here for further information).

OATH (Yubico Authenticator) - the YubiKey 5's OATH application can hold up to 32 OATH-TOTP credentials (AKA authenticator app codes).FIDO2 - the YubiKey 5 can hold up to 25 discoverable credentials in its FIDO2 application.FIDO U2F - similar to Yubico OTP, the U2F application can be registered with an unlimited number of services.However, Yubico OTP, one of the most popular kinds of credentials to put in this app, can be registered with an unlimited number of services. OTP - this application can hold two credentials.The limits for each protocol are summarized below. You can find setup instructions, as well as which protocol(s) a particular service uses on that service's entry in the Works With YubiKey Catalog, (eg. Which protocol will be used with a given account varies from service to service (website, app, etc.). YubiKeys from the 5 Series support 6 different protocols for two-factor authentication, each with its own limit on the number of accounts it can be associated with. If you are experiencing the error No Space Available in Yubico Authenticator, then you may have reached the account limit of your YubiKey for TOTP.

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