java.lang.NoClassDefFoundError: io.fabric.sdk.android.InitializationTask

[gofur]

I have crash on :
Samsung Galaxy S3
Android 4.3

error result :
FATAL EXCEPTION: main java.lang.NoClassDefFoundError: io.fabric.sdk.android.InitializationTask at io.fabric.sdk.android.Kit.<init>(Kit.java:45) at com.crashlytics.android.answers.Answers.<init>(Answers.java:22) at com.crashlytics.android.Crashlytics.<init>(Crashlytics.java:30) at com.crashlytics.android.CrashlyticsInitProvider.onCreate(CrashlyticsInitProvider.java:27) at android.content.ContentProvider.attachInfo(ContentProvider.java:1214) at android.content.ContentProvider.attachInfo(ContentProvider.java:1189) at android.app.ActivityThread.installProvider(ActivityThread.java:5119) at android.app.ActivityThread.installContentProviders(ActivityThread.java:4725) at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4665) at android.app.ActivityThread.access$1400(ActivityThread.java:159) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1376) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:176) at android.app.ActivityThread.main(ActivityThread.java:5419) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:525) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1046) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862) at dalvik.system.NativeStart.main(Native Method)

any one knows?