LumiSoft 邮件操作删除(无法删除解决方法)

最近在用 LumiSoft  进行邮件读取,然后操作相关附件
邮件使用的是qq邮箱,读取后进行移除,但是怎么都移除不了 后来咨询了官方客服,
原来是设置不对 需要 取消掉  X禁止收信软件删信 (仅对 POP3 协议有效。为什么会有收信软件删信？)

-----另外附上我写的相关代码

using LumiSoft.Net.Log;
using LumiSoft.Net.Mail;
using LumiSoft.Net.MIME;
using LumiSoft.Net.POP3.Client;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.IO;
using System.Net;
using System.Text;
using System.Linq;

namespace MCP.Sync.MailAttachCenter
{
    public class MailAttachCenterBiz
    {
       // const string smtp = "imap.exmail.qq.com";
        const string smtp = "pop.exmail.qq.com";

        const int smtpport = 995;
        const string user = "";
        const string pwd = "";
        const string dirfolder = @"D:\email\";
        const string FileServerUrl = "";

        const string module = "module_Sys_MailAttachCenter";
        const string folderId = "folderId_Sys_MailAttachCenter";

        public void SyncMail(ref string returnMessage)
        {

            using (POP3_Client pop3 = new POP3_Client())
            {
                //这里面存在无法删除邮件,所以导致只能通过去重的方式来处理重复读取的问题

                var attachList =new  List<MailAttach>();
                using (var db=new MCPERP_MailAttachEntities())
                {

                     attachList = db.Sys_MailAttachCenter.Select(s => new MailAttach {  MUID=s.MUID}).ToList();

                }

                pop3.Connect(smtp, smtpport, true);
                pop3.Login(user, pwd);//两个参数，前者为Email的账号，后者为Email的密码
                pop3.Logger = new Logger();
                pop3.Logger.WriteLog += new EventHandler<WriteLogEventArgs>(WriteLog);

                POP3_ClientMessageCollection messages = pop3.Messages;

                for (int i = 0; i < messages.Count; i++)
                {
                    var mEntity = new Sys_MailAttachCenter();
                    mEntity.SMTPServerName = smtp;

                    Dictionary<string, string> dic_file = new Dictionary<string, string>();

                    POP3_ClientMessage message = messages[i];//转化为POP3

                    if (attachList.Find(x=>x.MUID==message.UID)!=null)
                    {
                        continue;

                    }

                    pop3.Logger.AddText("\r\n正在检查第{0}封邮件..."+ i + 1);
                    if (message != null)
                    {
                        mEntity.MUID = message.UID;

                        byte[] messageBytes = message.MessageToByte();
                        if (messageBytes != null && messageBytes.Length > 0)
                        {

                            Mail_Message mime_message = Mail_Message.ParseFromByte(messageBytes);
                            Mail_Message mime_header = Mail_Message.ParseFromByte(message.HeaderToByte());
                            if (mime_header != null)
                            {
                                mEntity.Subject =!string.IsNullOrEmpty( mime_header.Subject)? mime_header.Subject.Trim():string.Empty;
                                mEntity.SendDT = mime_header.Date;
                                //区分抄送人
                                if (mime_header.Cc != null)
                                {
                                    StringBuilder sb = new StringBuilder();
                                    foreach (Mail_t_Mailbox recipient in mime_header.Cc.Mailboxes)
                                    {
                                        string displayname = recipient.DisplayName;
                                        string address = recipient.Address;

                                            sb.AppendFormat("{0};", address);

                                    }
                                    mEntity.CC = sb.ToString().Trim(';');
                                }

                                if (mime_header.From != null)
                                {
                                    StringBuilder sb = new StringBuilder();
                                    StringBuilder sb_sender = new StringBuilder();
                                    foreach (Mail_t_Mailbox recipient in mime_header.From)
                                    {
                                        string displayname = recipient.DisplayName;
                                        string address = recipient.Address;

                                        sb.AppendFormat("{0};", address);
                                        sb_sender.AppendFormat("{0};", displayname);

                                    }
                                    mEntity.Sender = sb_sender.ToString().Trim(';');
                                    mEntity.FromMail = sb.ToString().Trim(';');
                                }

                                if (mime_header.To != null)
                                {
                                    StringBuilder sb = new StringBuilder();
                                    foreach (Mail_t_Mailbox recipient in mime_header.To.Mailboxes)
                                    {
                                        string displayname = recipient.DisplayName;
                                        string address = recipient.Address;

                                            sb.AppendFormat("{0};", address);

                                    }
                                    mEntity.ToMail = sb.ToString().Trim(';');
                                }
                            }

                            var body = mime_message.BodyText;
                            if (body != null)
                            {
                                mEntity.Body = body.Length > 1000 ? "超长被截断--"+body.Substring(0,990) : body;
                            }

                            //保存邮件的整体附件
                            DirectoryInfo dir = new DirectoryInfo(dirfolder);
                            if (!dir.Exists) dir.Create();

                            string emailPath = dirfolder + message.UID + ".eml";
                            File.WriteAllBytes(emailPath, messageBytes);
                            dic_file.Add(Guid.NewGuid().ToString(), emailPath);

                            //附件处理
                            MIME_Entity[] attachments = mime_message.GetAttachments(true, true);
                            mEntity.AttachmentsCount = 1;
                            if (attachments != null && attachments.Length > 0)
                            {
                                mEntity.AttachmentsCount = mEntity.AttachmentsCount+attachments.Length;
                                foreach (MIME_Entity entity in attachments)
                                {
                                    if (entity.ContentDisposition != null)
                                    {
                                        string fileName = entity.ContentDisposition.Param_FileName;
                                        if (!string.IsNullOrEmpty(fileName))
                                        {
                                            var dirFileName = GetValidName(message.UID + fileName);
                                            string path = Path.Combine(dir.FullName, dirFileName);
                                            MIME_b_SinglepartBase byteObj = (MIME_b_SinglepartBase)entity.Body;
                                            Stream decodedDataStream = byteObj.GetDataStream();
                                            using (FileStream fs = new FileStream(path, FileMode.Create))
                                            {
                                                LumiSoft.Net.Net_Utils.StreamCopy(decodedDataStream, fs, 4000);
                                            }
                                            dic_file.Add(Guid.NewGuid().ToString(), path);

                                            //这里实现上传附件
                                            //上传成功以后删除本地缓存的附件

                                            pop3.Logger.AddText($"{fileName}已经被下载。");
                                        }
                                    }
                                }
                            }
                        }

                        var result = SaveFileToServer(dic_file, mEntity);//保存文件方法
                        if (result)
                        {
                            message.MarkForDeletion();//移除这个邮件
                        }
                    }
                }
            }
        }

        public static string GetValidName(string fileName)
        {
            foreach (char c in System.IO.Path.GetInvalidFileNameChars())
            {
                fileName = fileName.Replace(c, ' ');
            }
            return fileName;
        }
        private void WriteLog(object sender, WriteLogEventArgs e)
        {
            if (e!=null && e.LogEntry!=null)
            {

            }
        }

        /// <summary>
        /// 保存附件到文件服务器并添加到
        /// </summary>
        /// <returns></returns>
        private bool SaveFileToServer(Dictionary<string,string> dir,  Sys_MailAttachCenter mEntity)
        {
            try
            {
                if (mEntity!=null && dir.Count>0)
                {

                    var fList = new List<Sys_FileInfo>();

                    foreach (var item in dir)
                    {

                            string address = FileServerUrl + string.Format("Home/UploadFile?module={0}&folderId={1}&uploadDate={2}", module, folderId, DateTime.Now.ToString("yyyyMMdd"));
                            var buffer = new WebClient().UploadFile(address, "post", item.Value);
                            string result = Encoding.UTF8.GetString(buffer);
                            var fileServerPath = FileServerUrl + result.Replace("~/", "");
                            //判断文件是不是存在 清空临时存储的文件
                            if (System.IO.File.Exists(item.Value))
                            {
                                System.IO.File.Delete(item.Value);
                            }

                        Sys_FileInfo file = new Sys_FileInfo();
                        file.CreateDT = DateTime.Now;
                        file.CreaterName = module;
                        file.Description ="邮件附件处理中心创建";
                        file.FileType = Path.GetExtension(item.Value);
                        file.folderId = folderId;
                        file.module = module;
                        file.FileJobno = mEntity.MUID.ToString();
                        file.FileId = Guid.NewGuid().ToString("N");
                        file.EnabledMark = 1;
                        file.DeleteMark = 0;
                        file.FilePath = fileServerPath;
                        file.FileName = Path.GetFileName(item.Value);
                        file.FileExtensions = Path.GetExtension(item.Value);
                        fList.Add(file);

                    }

                    using (var db = new MCPERP_MailAttachEntities())
                    {

                        db.Sys_FileInfo.AddRange(fList);
                        mEntity.CreateDT = DateTime.Now;
                        mEntity.IsRead = false;
                        mEntity.IsReply = false;
                        db.Sys_MailAttachCenter.Add(mEntity);
                        db.SaveChanges();
                    }
                    return true;
                }

                return false;
            }
            catch (Exception ex)
            {

                throw ex;
            }
        }...

    }
    public class MailAttach
    {
        public string MUID { get; set; }
    }
}