Microsoft Store Operations POS: Attempt to process COM object 'ObjectName' failed. An unknown error ocurred.

I have a program that gets executed in POS. Occasionally POS closes that program in the midle of execution; after trying to restart it the error message shows "Attempt to process COM object 'ObjectName' failed. An unknown error occurred." I am invoking this program from Custom POS Button. Here is entry code. The exception below is never executed.

namespace FrameWiz { [ComVisible(true)] public class Startup { public bool Process(object argSession) { FrameWizShell frameWizShell = null; Session mySession = null;

try { //mine code here

return true; } catch(Exception) { throw; } finally { frameWizShell.Dispose(); mySession.Destroy(); } } } }