code: private SofaRpcException cannotFoundService(String appName, String serviceName) {
          String errorMsg = LogCodes
              .getLog(LogCodes.ERROR_PROVIDER_SERVICE_CANNOT_FOUND, serviceName);
          LOGGER.errorWithApp(appName, errorMsg);
          return new SofaRpcException(RpcErrorType.SERVER_NOT_FOUND_INVOKER, errorMsg);
      }
docs: 找不到服务
  
  @param appName     应用
  @param serviceName 服务
  @return 找不到服务的异常响应