How many threads can we run at a time.

We are using thread for fetching data. Sometimes it is possible that one thread depends on another so that situation second thread can't work without first thread output data. So this state is called deadlock.

AS per my understanding you are facing deadlock situation and it may be possible that your thread is sleep.

So you must sure that your thread is running when you are accessing data.

I will suggest to avoid timeout and page not found that make a thread asynchronous call of thread.
or check lock condition in thread so when this thread working on data then another thread can't work on same data

 lock( this )     {         _calcState = CalculationStatus.NotCalculating;         FireStatusChangedEvent( _calcState ); 

    }