The GoogleSignIn functionality in Unity can sometimes encounter issues on iOS devices when there are multiple (double) GoogleService-Info.plist files present. This is a common problem that can be fixed by following a few steps.
First, make sure that you have correctly added the GoogleService-Info.plist file to your Unity project. This file is required for the GoogleSignIn functionality to work properly. If you have multiple GoogleService-Info.plist files, check that you are using the correct one for your project.
Next, ensure that the GoogleSignIn plugin is set up correctly in the Unity Editor. Open the GoogleSignIn plugin settings by going to Edit -> Project Settings -> Google SignIn and verify that the GoogleService-Info.plist file is correctly referenced.
If you are still facing issues after verifying your setup, one possible solution is to remove any duplicate or unnecessary GoogleService-Info.plist files from your project. Having multiple copies of the file can cause conflicts and lead to unexpected behavior.
To remove the duplicates, go to your Unity project's Assets folder and search for all instances of the GoogleService-Info.plist file. Delete any duplicates or unused versions to ensure that only one copy remains.
Additionally, verify that the GoogleService-Info.plist file is correctly added to the Xcode project when building for iOS. To do this, select your iOS build target in Unity, go to the Player Settings, and ensure that the GoogleService-Info.plist file is included in the "Copy Plist Files" section.
After making these changes, rebuild your Unity project and deploy it to your iOS device. Test the GoogleSignIn functionality again, and it should now work correctly without any duplicate GoogleService-Info.plist issues.
In conclusion, to resolve the issue of GoogleSignIn not working on iOS with multiple GoogleService-Info.plist files in Unity, make sure that you have the correct file added to your project, remove any duplicates, and ensure it is correctly included in the build settings for Xcode. Following these steps should resolve the problem and allow you to use GoogleSignIn in your Unity project on iOS.