I'm currently facing an issue while integrating Sign in with Apple on a Firebase web app using JavaScript.
✅ What I’ve done:
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Created a Service ID
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Created an App ID and enabled Sign in with Apple
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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
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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:
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The client_id in the auth request matches the Service ID exactly
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I’m not using an iOS app — this is purely web-based Sign in with Apple
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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