I am getting error in the below coding when am grouping the details.Plz any one help me to sortout this error

List<ren> renewedorderlist = (from ordernum in salesContext.SL_OrderIdMapper
where ordernum.OrderNumber == placeOrderModel.OrderInfo.OrderID
from orderDetail in salesContext.SL_OrderDetails
where ordernum.OrderId == orderDetail.OrderId
 from renProducts in salesContext.products
where renProducts.pid == orderDetail.ProductID
from licenseDetails in salesContext.SL_LicenseDetails
where licenseDetails.OrderDetailId == orderDetail.OrderDetailId
from licenses in salesContext.SL_License
where licenses.LicenseId == licenseDetails.LicenseId
from oldProducts in salesContext.products
where oldProducts.pid == licenses.ProductID group licenses.LicenseId by ordernum.OrderId into g
select new ren
{
 OrderId=ordernum.OrderId,
 OldProductName = oldProducts.productdesc,
 NewProductName = renProducts.productdesc,
 Quantity = orderDetail.Quantity,
 LicenseID = licenses.LicenseId.ToString()
}).ToList<ren>();