CLR ICLRControl::GetCLRManager fails with error HOST_E_INVALIDOPERATION - c++

Question

I have a native process which uses .NET component via COM interop. Once the process is up, I am trying to get interface pointers to the various CLR managers such as ICLRDebugManager, ICLRGCManager, etc. using the ICLRControl interface pointer. I'm able to reach up to acquiring ICLRControl interface without a glitch. ICLRRuntimeInfo also correctly tells me that it is 4.0.x .net version when I call GetVersionString on it.
It is only that the ICLRControl::GetCLRManager keeps failing with error 0x80130122, which error code stands for HOST_E_INVALIDOPERATION. Searched the internet, but could not get information as to why this might be failing. Any help is much appreciated.
TIA.
WinCPP
Edit 1. Adding code snippet.
// ICLRRuntimeInfo interface pointer
CComQIPtr<ICLRRuntimeInfo> pCLRRuntimeInfo = pUnk;
if (!pCLRRuntimeInfo)
{
cout << "failed to get run time info interface pointer" << endl;
return;
}
TCHAR version[128];
memset(version, 0, 128);
DWORD count = 127;
pCLRRuntimeInfo->GetVersionString(version, &count);
cout << version << endl;
// ICLRRuntimeHost
CComPtr<ICLRRuntimeHost> pCLRRuntimeHost = 0;
hr = pCLRRuntimeInfo->GetInterface(CLSID_CLRRuntimeHost, IID_ICLRRuntimeHost, (LPVOID *)&pCLRRuntimeHost);
if (FAILED(hr))
{
cout << "failed to get run time host interface pointer" << endl;
return;
}
// ICLRControl
CComPtr<ICLRControl> pCLRControl = 0;
hr = pCLRRuntimeHost->GetCLRControl(&pCLRControl);
if (FAILED(hr))
{
cout << "failed to get clr control interface pointer" << endl;
return;
}
///////////////////////////////////////////
// Everything is successful upto this point
///////////////////////////////////////////
// ICLRGCManager
CComPtr<ICLRGCManager> pCLRGCManager = 0;
hr = pCLRControl->GetCLRManager(IID_ICLRGCManager, (LPVOID *)&pCLRGCManager);
if (FAILED(hr))
{
cout << "failed to get GC manager interface pointer" << endl;
return;
}
// Above call fails with the error 0x81031022, though everything is as per the MSDN documentation for the API

Answer 1

Looking at this source code on GitHub, it looks like CCorCLRControl::GetCLRManager will return HOST_E_INVALIDOPERATION if the runtime has already been started.
This explains why you are receiving that error code when attempting to "latch on to already loaded CLR instance," but that you meet with success when you create a CLR instance explicitly.