I am creating an android application with firebase sign in. The application is failing to sign in, the `AVD` has an internet connection, I checked several times. I checked `logcat` and found this error:

```
E/AuthUI: A sign-in error occurred.
    com.firebase.ui.auth.data.model.UserCancellationException: Unknown error
        at com.firebase.ui.auth.data.remote.GoogleSignInHandler.onActivityResult(GoogleSignInHandler.java:102)
        at com.firebase.ui.auth.ui.idp.AuthMethodPickerActivity.onActivityResult(AuthMethodPickerActivity.java:320)
        at android.app.Activity.dispatchActivityResult(Activity.java:6192)
        at android.app.ActivityThread.deliverResults(ActivityThread.java:3570)
        at android.app.ActivityThread.handleSendResult(ActivityThread.java:3617)
        at android.app.ActivityThread.access$1300(ActivityThread.java:151)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1352)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5254)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
08-03 23:18:34.698 4038-4038/com.example.kppvt E/AuthUI: A sign-in error occurred.
    com.firebase.ui.auth.data.model.UserCancellationException: Unknown error
        at com.firebase.ui.auth.data.remote.GoogleSignInHandler.onActivityResult(GoogleSignInHandler.java:102)
        at com.firebase.ui.auth.ui.idp.AuthMethodPickerActivity.onActivityResult(AuthMethodPickerActivity.java:320)
        at android.app.Activity.dispatchActivityResult(Activity.java:6192)
        at android.app.ActivityThread.deliverResults(ActivityThread.java:3570)
        at android.app.ActivityThread.handleSendResult(ActivityThread.java:3617)
        at android.app.ActivityThread.access$1300(ActivityThread.java:151)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1352)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5254)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

```