Web Api Go On Try and Return method but Return An error has occurred error : I Wrote an Api To Get Some Objects In Json Format . it get values in Linq Command and go To Return Method . but does not return my wanted values return ({
    "Message": "An error has occurred."
}) 

I Searched alot but did not find any thing yet . please Help me . and say what is the problem 

     public IHttpActionResult GetOrdersOfPostman(string postmanId)
        {
            try
            {
                var postmanCustomersModel = new List<PostmanCustomerModel>();
                var id = Convert.ToInt64(postmanId);

                var orderStatus = (byte) OrderStatus.DeliverToPostman;
                var orders = _orderRepository.AsQueryable().Where(x => x.PostmanId == id && x.OrderStatus==orderStatus &&
                             x.SellerCustomerId > 0).ToList();

                

                return Ok(orders);
            }
            catch (Exception ex)
            {
                return BadRequest(ex.Message);
            }
        }