FIX API Sample Engine Crashes

I am trying to use FIX API Sample Engine to use to implement my Robot for trading with FIX server. To understand how it works I am running it in MS Visual Studio and sending FIX messages by using button on GUI.  I have several questions on this.
Here is what I do to place Stop Order using Quote Prices:
1) Press "Logon" under Price stream. I get following messages:
sent message -- 8=FIX.4.4
9=128
35=A
49=circlemarkets.4000022
56=cServer
57=QUOTE
50=TRADE
34=1
52=20181119-12:20:46
98=0
108=30
141=Y
553=4000022
554=qwerty12
10=200

Receved message --

8=FIX.4.4
9=107
35=A
34=1
49=cServer
50=QUOTE
52=20181119-12:20:49.464
56=circlemarkets.4000022
57=TRADE
98=0
108=30
141=Y
10=118

Looks like valid messages.

2) Press "Spot Market Data Request" I get following messages:
Sent -- 8=FIX.4.4
9=150
35=V
49=circlemarkets.4000022
56=cServer
57=QUOTE
50=TRADE
34=2
52=20181119-12:22:47
262=EURUSD:WDqsoT
263=1
264=1
265=1
267=2
269=0
269=1
146=1
55=1
10=214

Received -- 8=FIX.4.4
9=89
35=0
34=2
49=cServer
50=QUOTE
52=20181119-12:21:20.012
56=circlemarkets.4000022
57=TRADE
10=228

Not sure why there is 35=0 in response to 35=V???

3)I press "Logon" button under "Trade Stream" and I get following messages:
Sent -- 8=FIX.4.4
9=122
35=A
49=circlemarkets.4000022
56=cServer
57=TRADE
50=TRADE
34=3
52=20181119-12:24:52
98=0
108=30
553=4000022
554=qwerty12
10=122

Received -- 8=FIX.4.4
9=101
35=A
34=1
49=cServer
50=TRADE
52=20181119-12:24:54.715
56=circlemarkets.4000022
57=TRADE
98=0
108=30
10=036

Looks like valid messages

4) I press "New Stop Order Single" button and the response is as follows:
Sent -- 8=FIX.4.4
9=148
35=D
49=circlemarkets.4000022
56=cServer
57=TRADE
50=TRADE
34=4
52=20181119-12:26:38
11=10
55=1
54=1
60=20181119-12:26:38
38=1000
40=3
99=1.15
59=3
10=172

Received -- 8=FIX.4.4
9=89
35=0
34=2
49=cServer
50=TRADE
52=20181119-12:25:25.062
56=circlemarkets.4000022
57=TRADE
10=212

I sent 35=D (new single Order message and in response I received 35=0 Heart beat message. Why is this? I was expecting 35=8 that is execution report. Not sure why. Could you please explain?

5)Next I once again send by pressing "New Stop Order Single" and MS Visual Studio crashed with following detailed messages:

---message starts-------------
System.IO.IOException
  HResult=0x80131620
  Message=Unable to write data to the transport connection: An established connection was aborted by the software in your host machine.
  Source=System
  StackTrace:
   at System.Net.Sockets.NetworkStream.Write(Byte[] buffer, Int32 offset, Int32 size)
   at System.Net.Security._SslStream.StartWriting(Byte[] buffer, Int32 offset, Int32 count, AsyncProtocolRequest asyncRequest)
   at System.Net.Security._SslStream.ProcessWrite(Byte[] buffer, Int32 offset, Int32 count, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.Write(Byte[] buffer, Int32 offset, Int32 count)
   at FIX_API_Sample.frmFIXAPISample.SendMessage(String message, SslStream stream, Boolean readResponse) in C:\Users\net_r\Downloads\latestDownLoads\FIX-API-Sample-master1\FIX-API-Sample-master\FIX API Sample.cs:line 102
   at FIX_API_Sample.frmFIXAPISample.SendTradeMessage(String message, Boolean readResponse) in C:\Users\net_r\Downloads\latestDownLoads\FIX-API-Sample-master1\FIX-API-Sample-master\FIX API Sample.cs:line 95
   at FIX_API_Sample.frmFIXAPISample.btnStopOrder_Click(Object sender, EventArgs e) in C:\Users\net_r\Downloads\latestDownLoads\FIX-API-Sample-master1\FIX-API-Sample-master\FIX API Sample.cs:line 272
   at System.Windows.Forms.Control.OnClick(EventArgs e)
   at System.Windows.Forms.Button.OnClick(EventArgs e)
   at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ButtonBase.WndProc(Message& m)
   at System.Windows.Forms.Button.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
   at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.Run(Form mainForm)
   at FIX_API_Sample.Program.Main() in C:\Users\net_r\Downloads\latestDownLoads\FIX-API-Sample-master1\FIX-API-Sample-master\Program.cs:line 20

Inner Exception 1:
SocketException: An established connection was aborted by the software in your host machine

---End messages--------------

I see this crash quite often and not sure how to fix this. I am using your FIX API Sample code  without any modification. 

Is it wrong to press two consecutive "New Stop Order Singles" buttons?

For every Order placed using "New Stop Order Single" button I should look for receiving 35=8 message to decode and figure out the status of Stop order placed. However, this 35=8 message I receive very randomly, sometime I get 35=2 that ResendMessage and I Press "Resend Request" Button and after pressing this button few more times I get 35=8 message similarly I press sometime "Order Status Request" button and I receive 35=8 messate after a while.

Could you please help me in giving more insight on this so that I can build my cTrader based FIX engine using your sample code. By the way you are providing great service by giving this Sample code to jump start FIX engine development process. 

I comlpeted coding of my Robot built around this sample code but decoding received FIX messages is a BIG issue.
Please give me insight into this code that will help me greatly in developing my FIX Engine based Robot.

Thanks