Facebook Login With Using firebase Auth in unity - firebase

Question

I am usign Firebase for the logins with gmail and facebook i am sharing the code below its working in the Game mode in unity but after building the apk after that we click on the fb assigned button on android device the app stops workign As i have fallowed the document give in firebase and facebook developer example doc
https://firebase.google.com/docs/auth/unity/facebook-login
https://developers.facebook.com/docs/unity/examples
using Facebook.Unity;
using Firebase.Auth;
void Awake()
{
if (!FB.IsInitialized)
{
// Initialize the Facebook SDK
FB.Init(InitCallback, OnHideUnity);
}
else
{
// Already initialized, signal an app activation App Event
FB.ActivateApp();
}
}
private void InitCallback()
{
if (FB.IsInitialized)
{
// Signal an app activation App Event
FB.ActivateApp();
// Continue with Facebook SDK
// ...
}
else
{
Debug.Log("Failed to Initialize the Facebook SDK");
}
}
private void OnHideUnity(bool isGameShown)
{
if (!isGameShown)
{
// Pause the game - we will need to hide
Time.timeScale = 0;
}
else
{
// Resume the game - we're getting focus again
Time.timeScale = 1;
}
}
public void loginfb()
{
var perms = new List<string>() { "public_profile", "email" };
FB.LogInWithReadPermissions(perms, AuthCallback);
}
private void AuthCallback(ILoginResult result)
{
if (FB.IsLoggedIn)
{
// AccessToken class will have session details
var aToken = Facebook.Unity.AccessToken.CurrentAccessToken;
// Print current access token's User ID
Debug.Log(aToken.UserId);
// Print current access token's granted permissions
foreach (string perm in aToken.Permissions)
{
Debug.Log(perm);
}
}
else
{
Debug.Log("User cancelled login");
}
}
Firebase.Auth.FirebaseAuth auth;
public void loginviaFirebaseFacebook(String accessToken)
{
auth = Firebase.Auth.FirebaseAuth.DefaultInstance;
Firebase.Auth.Credential credential =
Firebase.Auth.FacebookAuthProvider.GetCredential(accessToken);
auth.SignInWithCredentialAsync(credential).ContinueWith(task =>
{
if (task.IsCanceled)
{
Debug.LogError("SignInWithCredentialAsync was canceled.");
return;
}
if (task.IsFaulted)
{
Debug.LogError("SignInWithCredentialAsync encountered an error: " + task.Exception);
return;
}
Firebase.Auth.FirebaseUser newUser = task.Result;
Debug.LogFormat("User signed in successfully: {0} ({1})",
newUser.DisplayName, newUser.UserId);
});
}