Unity Firebase Google SignIn Error Help

Hello everyone! I'm in a bit of a pickle here. I am making making a unity 2D game and recently decided to add Firebase Authentication as a feature of the game. I've added the Email SignIn and Facebook SignIn buttons which both work. I then enabled the Google SignIn method in Firebase Console, followed all of the documentation steps and managed to get it work briefly. After about 15 minutes of working each new sign in gives the following error:

 Got Error: DeveloperError Exception of type 'Google.GoogleSignIn+SignInException' was thrown.
 GoogleLogin:OnAuthenticationFinished(Task`1)
 System.Threading.ThreadPoolWorkQueue:Dispatch()

I haven't managed to find any relevant help online, even reverting to the previous version via Github doesn't seem to solve anything.

If anyone could help me in correcting this, that would be great. Thanks in advance.