If your account has two-step verification, signing in with the correct password, Google account or Apple account may still require another check. Use your configured authenticator, or choose WhatsApp if you already have a verified phone factor. Phone codes use the same WhatsApp verification service as Keystonne OS; SMS and standalone phone sign-in are not offered in Keystonne Account.
If your usual factor is unavailable, use the recovery option already offered for your account. Recovery codes are private credentials: enter one only in the recovery form. Do not paste one into KAI or a support request.
Account help can explain the published recovery steps. It cannot bypass verification, remove a factor simply because someone knows an email address, or grant business access. If a connection expires while you complete verification, return to the original service and start sign-in again.