Credential Provider not working for Windows 2012 R1 Standard Server

Question

Hey,one issue i'm seeing with windows 2012 r1 standard server is that the ICredentialProvider::GetFieldDescriptorAt method isn't getting called at logon which is causing a blank logon screen with fields not getting populated. All other methods under ICredentialProvider are getting called.

The same plugin is working fine with windows 2012 r1 and r2 datacenter servers as well as 2012 r2 standard server.

snapshot of the GetFieldDescriptorAt method

public int GetFieldDescriptorAt(uint dwIndex, [Out] IntPtr ppcpfd) 
        {
            Log.LogMethodCall();
            if (dwIndex >= credentialTile.CredentialProviderFieldDescriptorList.Count)
            {
                return HResultValues.E_INVALIDARG;
            }

            var listItem = credentialTile.CredentialProviderFieldDescriptorList[(int) dwIndex];
            var pcpfd = Marshal.AllocCoTaskMem(Marshal.SizeOf(listItem)); 
            Marshal.StructureToPtr(listItem, pcpfd, false); 
            Marshal.StructureToPtr(pcpfd, ppcpfd, false); 

            return HResultValues.S_OK;
}