Fórum Erro ao Serializar Objeto(Classe) em XML CSharp #519113

        public static string ObjectToXml<T>(T obj)
        {
            XmlSerializer serializer = new XmlSerializer(typeof(T));
            StringWriter strWriter = new StringWriter();
            XmlWriter xmlWriter = XmlWriter.Create(strWriter);
            serializer.Serialize(xmlWriter, obj);
            return RemoveAllNamespaces(strWriter.ToString());
        }

        //Implemented based on interface, not part of algorithm
        public static string RemoveAllNamespaces(string xmlDocument)
        {
            XElement xmlDocumentWithoutNs = RemoveAllNamespaces(XElement.Parse(xmlDocument));

            return xmlDocumentWithoutNs.ToString();
        }

        //Core recursion function
        private static XElement RemoveAllNamespaces(XElement xmlDocument)
        {
            if (!xmlDocument.HasElements)
            {
                XElement xElement = new XElement(xmlDocument.Name.LocalName);
                xElement.Value = xmlDocument.Value;

                foreach (XAttribute attribute in xmlDocument.Attributes())
                    xElement.Add(attribute);

                return xElement;
            }
            return new XElement(xmlDocument.Name.LocalName, xmlDocument.Elements().Select(el => RemoveAllNamespaces(el)));
        }

[DataContract]
    public class Invoiced
    {
        [DataMember]
        public int number { get; set; }
        [DataMember]
        public int line { get; set; }
        [DataMember]
        public string issueDate { get; set; }
        [DataMember]
        public string key { get; set; }
    }
    
    [DataContract]
    public class Pf
    {
        [DataMember]
        public string cpf { get; set; }
        [DataMember]
        public string name { get; set; }
    }
    
    [DataContract]
    public class Pj
    {
        [DataMember]
        public string cnpj { get; set; }
        [DataMember]
        public string corporateName { get; set; }
    }
    
    [DataContract]
    public class DeliveryAddress
    {
        [DataMember]
        public string neighborhood { get; set; }
        [DataMember]
        public string city { get; set; }
        [DataMember]
        public string zipcode { get; set; }
        [DataMember]
        public string street { get; set; }
        [DataMember]
        public string additionalInfo { get; set; }
        [DataMember]
        public string state { get; set; }
        [DataMember]
        public string number { get; set; }
        [DataMember]
        public string country { get; set; }
        [DataMember]
        public string reference { get; set; }
    }

    [DataContract]
    public class Main
    {
        [DataMember]
        public string ddd { get; set; }
        [DataMember]
        public string number { get; set; }
    }

    [DataContract]
    public class Secondary
    {
        [DataMember]
        public string ddd { get; set; }
        [DataMember]
        public string number { get; set; }
    }

    [DataContract]
    public class Business
    {
        [DataMember]
        public string ddd { get; set; }
        [DataMember]
        public string number { get; set; }
    }

    [DataContract]
    public class Telephones
    {
        [DataMember]
        public Main main { get; set; }
        [DataMember]
        public Secondary secondary { get; set; }
        [DataMember]
        public Business business { get; set; }
    }

    [DataContract]
    public class Customer
    {
        [DataMember]
        public Pf pf { get; set; }
        [DataMember]
        public Pj pj { get; set; }
        [DataMember]
        public DeliveryAddress deliveryAddress { get; set; }
        [DataMember]
        public Telephones telephones { get; set; }
    }

    [DataContract]
    public class Link
    {
        [DataMember]
        public string id { get; set; }
        [DataMember]
        public string rel { get; set; }
        [DataMember]
        public string href { get; set; }
    }

    [DataContract]
    public class Product
    {
        [DataMember]
        public Link link { get; set; }
        [DataMember]
        public int quantity { get; set; }
        [DataMember]
        public double price { get; set; }
        [DataMember]
        public double freight { get; set; }
        [DataMember]
        public double discount { get; set; }
    }

    [DataContract]
    public class Order
    {
        [DataMember]
        public string id { get; set; }
        [DataMember]
        public string siteId { get; set; }
        [DataMember]
        public string purchaseDate { get; set; }
        [DataMember]
        public string store { get; set; }
        [DataMember]
        public string lastUpdate { get; set; }
        [DataMember]
        public string status { get; set; }
        [DataMember]
        public Invoiced invoiced { get; set; }
        [DataMember]
        public string estimatedDeliveryDate { get; set; }
        [DataMember]
        public Customer customer { get; set; }
        [DataMember]
        public double totalAmount { get; set; }
        [DataMember]
        public double totalFreight { get; set; }
        [DataMember]
        public double totalDiscount { get; set; }
        [DataMember]
        public List<Product> products { get; set; }
    }

    [DataContract]
    public class Pedidos
    {
        [DataMember]
        public List<Order> orders { get; set; }
        [DataMember]
        public int total { get; set; }
    }

Pedidos pedido = JsonHelper.JsonDeserialize<Pedidos>(lJson);

string xmlPedidos = ObjectToXml<Pedidos>(pedido);