Via NFC FIDO2 is working, the website you visit while using NFC is the so-called "ndef" app, this will start if there is no other request pending from your nfc-reader (smartphone). Please try to test NFC & FIDO2 through a website like: webauthn.io ... If it's not working please write support (at) nitrokey (dot) com, because your Nitrokey might be not fully functional.