While trying to iterate I am getting this error : io.grpc.StatusRuntimeException: PERMISSION_DENIED: unknown request. My client has admin privilege. What am I missing ?

WatchServiceOuterClass.WatchRequest request = WatchServiceOuterClass.WatchRequest.newBuilder().build();
            Iterator<WatchServiceOuterClass.WatchResponse> responseList = watchService.watch(request);
            for (Iterator i = responseList; i.hasNext(); )
                System.out.println(i.next());