Upgraded to premium to use with yubikey 4

keep getting invalid key when trying to set up ???

I don’t have the premium, but another person on this forum mentioned problems with Yubico OTP but not with U2F. Are you using U2f or OTP?

tried both m8 but not having any luck, i have another yubikey 4 with slightly newer firmware which works fine just bought this one with older firmware which i bought from ebay, i wanted two yubikeys for bitwarden

Since they were brought from Ebay, Have you validate that they are valid Yubikey.

ye deffo legit yubikey, i can use key on gmail no problem just not bitwarden

What platform are you using this on and what interface? Is this on windows? Using usb or nfc?

It might help if you tell us the level of the firmware which works and that which does not.

I have two of those, bought from Ebay, and both work fine.

Im using it on windows and usb, Firmware of the one thats not working correctly is 4.3.1
and the one ive had for over two years which works fine is 4.3.4

Sorry, none of mine have that firmware. Mine are 4.3.7 and 4.3.4 and both work fine.

Thanks, you are using this on windows. Are you using Fido/U2f or OTP?