Locked out?

Three ways back, in this order.

1. Try another device where you set up a passkey.Passkeys often sync between your devices.
2. Use your personal key if you saved it.It's on the sign-in page under "Use a personal key instead".
3. Ask an admin to send you a new sign-in link.You'll set up a fresh passkey from it.

If you are the only admin, the person who runs this server can issue a one-time link for you.