Apple Sign In "Sign up not completed" Error

Apple Sign In - "Sign up not completed" Error in Development Build (React Native / Expo)

Problem Summary

I'm implementing Apple Sign In in a React Native app using expo-apple-authentication. The Apple sign-in dialog appears as expected, but after tapping "Continue," it displays the message: "Sign up not completed". No credential is returned, and the promise eventually rejects with ERR_REQUEST_CANCELED.

App Configuration

• Platform: React Native (Expo SDK 52)
• Library: expo-apple-authentication v7.1.3
• Target: iOS development build (not Expo Go)
• Bundle ID: com.example.appname.nativetest (new App ID created for testing)

Apple Developer Console Setup (Reviewed Carefully)

App ID

• Explicit App ID (not a wildcard)
• "Sign In with Apple" capability enabled
• No associated Services IDs or Sign In with Apple Keys

Provisioning Profile

• Development profile created for the test App ID
• Profile includes the test device and development certificate
• Installed successfully and used to sign the app

Certificates and Signing

• Valid Apple Developer Program membership
• Development certificate installed and selected during build
• App installs and launches properly on the test device

Implementation Attempts

Attempt 1: Supabase OAuth Method

Initially tried using Supabase’s built-in Apple OAuth provider:

• Configured with team ID, key ID, and JWT credentials
• Proper redirect URLs and scheme were in place
• Resulted in OAuth URL pointing to Supabase instead of Apple, with incomplete client ID
• Ultimately moved to native implementation for improved control and reliability

Attempt 2: Native Apple Sign In (Current Approach)

Using expo-apple-authentication with the following code:

const credential = await AppleAuthentication.signInAsync({
  requestedScopes: [
    AppleAuthentication.AppleAuthenticationScope.FULL_NAME,
    AppleAuthentication.AppleAuthenticationScope.EMAIL,
  ],
});

Relevant app.config.js Section:

ios: {
  bundleIdentifier: 'com.example.appname.nativetest',
  usesAppleSignIn: true,
  infoPlist: {
    NSAppTransportSecurity: {
      NSAllowsArbitraryLoads: true,
      NSAllowsLocalNetworking: true,
    },
  },
},
plugins: ['expo-apple-authentication']

Observed Behavior

AppleAuthentication.isAvailableAsync() → true
Credential state → NOT_FOUND (expected for new user)
Apple Sign In dialog appears and allows interaction
User taps "Continue" → dialog reports "Sign up not completed"
Eventually returns: [Error: The user canceled the authorization attempt], code ERR_REQUEST_CANCELED

Confirmed Working Aspects

• AppleAuthentication API is available and initialized
• App is signed correctly and launches on the physical test device
• Apple Sign In dialog appears with correct styling and options
• Same result observed across both Wi-Fi and cellular networks

Clean Setup and Debugging Performed

• Removed all previous build artifacts
• Created a new App ID and new provisioning profile
• Rebuilt the app using expo run:ios --device
• Validated entitlements and provisioning assignments
• Removed any Services IDs and Apple Sign In keys used in previous attempts
• Verified ATS (App Transport Security) policies allow dev-time communication

Environment Information

• Device: iPhone (not simulator)
• iOS Version: 18.5
• Xcode: Latest version
• Apple ID: Developer account with 2FA enabled
• Build Method: EAS CLI using expo run:ios --device

Open Questions

1. Has anyone experienced the "Sign up not completed" issue with a clean native implementation in Expo?
2. Are there known limitations when testing Apple Sign In in local development builds?
3. Could prior Apple ID authorization attempts impact sign-in behavior during testing?
4. Are there any additional configuration steps, Info.plist changes, or entitlements required beyond those listed above?

Thank you in advance for any suggestions or guidance. We’re hoping this is simply a configuration detail that needs to be adjusted.