Unable to add to window

[AkshayBaldia]

i can't understand this issue and this is only in onePlus 3 device

Fatal Exception: java.lang.RuntimeException: Unable to create service com.skytesters.app.floatingmenu.service.ServiceFloating: android.view.WindowManager$BadTokenException: Unable to add window -- window android.view.ViewRootImpl$W@efad162 has already been added at android.app.ActivityThread.handleCreateService(ActivityThread.java:3308) at android.app.ActivityThread.-wrap5(ActivityThread.java) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1617) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:154) at android.app.ActivityThread.main(ActivityThread.java:6290) at java.lang.reflect.Method.invoke(Method.java) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776) Caused by android.view.WindowManager$BadTokenException: Unable to add window -- window android.view.ViewRootImpl$W@efad162 has already been added at android.view.ViewRootImpl.setView(ViewRootImpl.java:709) at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:342) at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:94) at com.skytesters.app.floatingmenu.service.ServiceFloating.onCreate(ServiceFloating.java:61) at android.app.ActivityThread.handleCreateService(ActivityThread.java:3298) at android.app.ActivityThread.-wrap5(ActivityThread.java) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1617) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:154) at android.app.ActivityThread.main(ActivityThread.java:6290) at java.lang.reflect.Method.invoke(Method.java) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)