Harmont docs
APIErrors

passkey_assertion_failed

The passkey signature did not validate.

HTTP status400
typeinvalid_request
codepasskey_assertion_failed
Default messageThat passkey signature could not be verified. Try signing in again.

When this happens

Your authenticator produced a signature that did not verify against the stored public key. This can follow a corrupted credential, a mismatched origin (for example, signing in from a different domain than the one you registered), or a browser extension interfering with WebAuthn.

How to fix it

Try the sign-in again. If it keeps failing, register a new passkey from a trusted device on the official domain, or sign in with Google/GitHub and add a fresh passkey from settings. The response message includes a specific reason after the colon.

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