Notchr unlocks your ledger with a secret your passkey derives (the WebAuthn PRF extension). Not every passkey app can do it, and some can only do it on some devices. This says what yours does, here.
Each button opens one passkey prompt, and each needs its own tap. If a prompt fails, run the second check and pick the same passkey: if it works there, its app is refusing the encryption key rather than failing to sign. If a check says the browser refused without opening a prompt, reload this page first — on iPhone and iPad that is the only thing that clears it. To test one app in particular, pick it in the sheet; the test passkey is never registered with Notchr, so delete it from that app afterwards.