I'm currently facing an issue while integrating Sign in with Apple on a Firebase web app using JavaScript. ✅ What I’ve done: Created a Service ID Created an App ID and enabled Sign in with Apple Linked the Service ID to the App ID under Web Authentication Configuration and also add these Domains and sub-domains: apple-signin-test-next.firebaseapp.com Registered return URL: https://apple-signin-test-next.firebaseapp.com/__/auth/handler Generated a key with Sign in with Apple capability and added: Key ID Team ID Private Key Client ID (Service ID not App ID) all in the Firebase Auth Apple Sign-In configuration I’ve tried multiple test projects and keys, including deleting and recreating everything, but I still consistently receive this error: invalid_client 🔎 Additional Details: The client_id in the auth request matches the Service ID exactly I’m not using an iOS app — this is purely web-based Sign in with Apple I am using a valid Apple Developer account enrolled in the program What could be the reason Apple keeps returning invalid_client even though all configuration seems correct? Please help us to resolve the issue. We are ready to connect for a call too. Thanks