For user registration/login we need it to be under FIDO and therefore we are going to use webthaun as the second factor. The problem is that to use the FIDO security key, we can’t link the same device, it asks us to use a USB key or another different device. Is it possible to configure it to link only one device? Thanks
Hi @tomas.aguilar ! I’m not sure I understand your question but let’s see if I can break it down.
For user registration/login we need it to be under FIDO
Do you mean you want to use passkeys? If that’s the case, you can enroll a passkey and also set Webauthn MFA with a Security Key as another factor.
The problem is that to use the FIDO security key, we can’t link the same device, it asks us to use a USB key or another different device.
Under the assumption that you want to use passkeys, you can have your passkey created in your security key and use the same security key as the key for MFA with Webauthn as well. Auth0 will prompt you (depending on your local enrolment settings) if you wish to create a new passkey in the current device you’re using (for example your laptop) but you can skip this and only use the passkey created in your security key.
Let me know if this is helpful, otherwise if you can give me a bit more detail on what you’re trying to do that’d be great! 
Yes, I’m sorry because I didn’t explain myself well.
The flow would be to login with passwordless with sms or email and then use as second authentication factor “MFA webthaun FIDO Security Keys”. When I configure this MFA on my device, it asks me to use a second device to store this key. I want to save this MFA on the same device. I don’t know if I have explained myself better. Thanks