My Meta Partner embed form is failing right at the final confirmation step when users try to link their WhatsApp accounts. Everything works until that last click, then a specific error message pops up and the account simply won’t link. I need a Facebook-qualified developer who understands the Meta Partner framework, the embedded signup flow, Graph API calls, and the WhatsApp Business onboarding sequence to pinpoint and eliminate whatever is blocking that final confirmation. Access to the current implementation and error logs is ready; as soon as the root cause is identified I expect a patched script or clear configuration fix that lets every new user complete the link without further issues. Deliverable: a fully functioning embed form that carries users through to a successful WhatsApp account connection, plus a brief note on what was wrong and how it was corrected so I can avoid the same pitfall in future updates.