In this post, you’ll learn more about the Error RPC_E_CANTPOST_INSENDCALL – 0x80010003 that is returned when working with the COM-based APIs in Win32
Win32 COM Error
RPC_E_CANTPOST_INSENDCALL – 0x80010003
Win32 COM Error Error Description
The caller is dispatching an intertask SendMessage call and cannot call out via PostMessage.