Ошибка при запросе ключей Net Core

public static List<uint> GetKeys()
        {
            List<uint> donglesIDs = new List<uint>();

            uint dongleID;

            Handle grdHandle = new Handle();
            FindInfo grdFindInfo1;
            GrdE retCode;

            retCode = GrdApi.GrdStartup(GrdFMR.Local);
            ErrorHandling(grdHandle, retCode);

            grdHandle = GrdApi.GrdCreateHandle(GrdCHM.MultiThread);
            retCode = GrdApi.GrdSetAccessCodes(grdHandle, GuardantConfiguration.PublicCode, GuardantConfiguration.ReadCode, 0, 0);
            ErrorHandling(grdHandle, retCode);
            retCode = GrdApi.GrdFind(grdHandle, GrdF.First, out dongleID, out grdFindInfo1);

            while (retCode == GrdE.OK)
            {
                donglesIDs.Add(dongleID);
                retCode = GrdApi.GrdFind(grdHandle, GrdF.Next, out dongleID, out grdFindInfo1);
            }
            CloseKey(grdHandle);

            return donglesIDs;
        }