New Post: pplx Exception

I have some problem with below message.
This message appeared when i tried to send many request about 300 times.

~_ExceptionHolder()

    {
        if (_M_exceptionObserved == 0)
        {
            // If you are trapped here, it means an exception thrown in task chain didn't get handled.
            // Please add task-based continuation to handle all exceptions coming from tasks.
            // this->_M_stackTrace keeps the creation callstack of the task generates this exception.
            _REPORT_PPLTASK_UNOBSERVED_EXCEPTION();   <<<<- call stack stop
        }
    }

And call stack is
H2Viewer.exe!pplx::details::_ExceptionHolder::~_ExceptionHolder() 931
H2Viewer.exe!pplx::details::_ExceptionHolder::scalar deleting destructor'(unsigned int)
H2Viewer.exe!std::_Ref_count_obj<pplx::details::_ExceptionHolder>::_Destroy() 885 H2Viewer.exe!std::_Ref_count_base::_Decref() 120
H2Viewer.exe!std::_Ptr_base<pplx::details::_ExceptionHolder>::_Decref() 347 H2Viewer.exe!std::shared_ptr<pplx::details::_ExceptionHolder>::~shared_ptr<pplx::details::_ExceptionHolder>() 624
H2Viewer.exe!pplx::details::_Task_impl_base::~_Task_impl_base() 1697
H2Viewer.exe!pplx::details::_Task_impl<unsigned char>::~_Task_impl<unsigned char>() 2387
H2Viewer.exe!pplx::details::_Task_impl<unsigned char>::scalar deleting destructor'(unsigned int)
H2Viewer.exe!std::_Ref_count_obj<pplx::details::_Task_impl<unsigned char> >::_Destroy() 884
H2Viewer.exe!std::_Ref_count_base::_Decref() 120
H2Viewer.exe!std::_Ptr_base<pplx::details::_Task_impl<unsigned char> >::_Decref() 347
H2Viewer.exe!std::shared_ptr<pplx::details::_Task_impl<unsigned char> >::~shared_ptr<pplx::details::_Task_impl<unsigned char> >() 624
H2Viewer.exe!pplx::details::_PPLTaskHandle<unsigned char,pplx::task<std::vector<unsigned char,std::allocator<unsigned char> > >::_ContinuationTaskHandle<std::vector<unsigned char,std::allocator<unsigned char> >,void,<lambda_bb02b3f8e611285d839efd2f7bdc8b0e>,std::integral_constant<bool,1>,pplx::details::_TypeSelectorNoAsync>,pplx::details::_ContinuationTaskHandleBase>::~_PPLTaskHandle<unsigned char,pplx::task<std::vector<unsigned char,std::allocator<unsigned char> > >::_ContinuationTaskHandle<std::vector<unsigned char,std::allocator<unsigned char> >,void,<lambda_bb02b3f8e611285d839efd2f7bdc8b0e>,std::integral_constant<bool,1>,pplx::details::_TypeSelectorNoAsync>,pplx::details::_ContinuationTaskHandleBase>() 1605
H2Viewer.exe!pplx::task<std::vector<unsigned char,std::allocator<unsigned char> > >::_ContinuationTaskHandle<std::vector<unsigned char,std::allocator<unsigned char> >,void,<lambda_bb02b3f8e611285d839efd2f7bdc8b0e>,std::integral_constant<bool,1>,pplx::details::_TypeSelectorNoAsync>::~_ContinuationTaskHandle<std::vector<unsigned char,std::allocator<unsigned char> >,void,<lambda_bb02b3f8e611285d839efd2f7bdc8b0e>,std::integral_constant<bool,1>,pplx::details::_TypeSelectorNoAsync>() 3780
H2Viewer.exe!pplx::task<std::vector<unsigned char,std::allocator<unsigned char> > >::_ContinuationTaskHandle<std::vector<unsigned char,std::allocator<unsigned char> >,void,<lambda_bb02b3f8e611285d839efd2f7bdc8b0e>,std::integral_constant<bool,1>,pplx::details::_TypeSelectorNoAsync>::`scalar deleting destructor'(unsigned int)

H2Viewer.exe!pplx::details::_AutoDeleter<pplx::details::_TaskProcHandle>::~_AutoDeleter<pplx::details::_TaskProcHandle>() 108

H2Viewer.exe!pplx::details::_TaskProcHandle::_RunChoreBridge(void * _Parameter) 126
cpprest110d_1_4.dll!pplx::details::_Scheduler_Param::DefaultWorkCallback(struct _TP_CALLBACK_INSTANCE *,void *,struct _TP_WORK *)

I wish you to tell me what to do.
thank you.