Mailkit is not sending proper html body

I am trying to send a simple <ul><li> something </l></ul> html but any reciept is not showing proper html

here is my code

  string  MainMailTo = "";
            //************
            MimeMessage message = new MimeMessage();
            //************
            var SMTP = Configuration.GetSection("EmailConfiguration:SMTPServer");
            var Port = Configuration.GetSection("EmailConfiguration:SMTPPort");
            var MailSender = Configuration.GetSection("EmailConfiguration:FromEmail");
            var MailPass = Configuration.GetSection("EmailConfiguration:Password");
            var SSlEnabled = Configuration.GetSection("EmailConfiguration:IsSSL");
            var MailUser = Configuration.GetSection("EmailConfiguration:MailUser");

            //************
            var MailTo = param.ToEmail;

            //************
            MailboxAddress from = new MailboxAddress("noreply", MailSender.Value);
            message.From.Add(from);
            //************
            string[] mailToList = MainMailTo.Split(new String[] { ";" }, StringSplitOptions.RemoveEmptyEntries);
            foreach (var item in MailTo.Split(new String[] { ";" }, StringSplitOptions.RemoveEmptyEntries))
            {
                mailToList.Append(item);
            }
           
            MailboxAddress to = new MailboxAddress("User", MailTo);
            message.To.Add(to);
            //************
            message.Subject = param.Subject;
            //************
            BodyBuilder bodyBuilder = new BodyBuilder();
            bodyBuilder.HtmlBody = param.BodyHTML;
            bodyBuilder.TextBody = "-";

          

            if (param.FileIds?.Count > 0)
            {
                foreach (int id in param.FileIds)
                {
                    var fileObj = dBContext.Documents.Where(x => x.DocumentId == id).FirstOrDefault();
                    if (fileObj != null)
                    {
                        var pathCombine = System.IO.Path.Combine(this.environment.WebRootPath, fileObj.Path);
                      
                        bodyBuilder.Attachments.Add(pathCombine);
                    }
                }
            }

            try
            {
                message.Body = bodyBuilder.ToMessageBody();
               
                SmtpClient client = new SmtpClient();
                
                client.Connect(SMTP.Value, Convert.ToInt32(Port.Value), Convert.ToBoolean(SSlEnabled.Value));
                client.Authenticate(MailUser.Value, MailPass.Value);
                //************
                client.Send(message);
                client.Disconnect(true);
                client.Dispose();
                return "true";
            }
            catch (Exception exp)
            {
                return exp.Message;
            }

[jstedfast]

If you print param.BodyHTML to a text file (or to the Console), you’ll notice that the value already encodes < as < and > as > which is what is causing your problem.

In other words, the param.BodyHTML string is already broken before you give it to MimeKit/MailKit.

[jstedfast]

I need to know what the raw message looks like so I can see the MIME and MIME headers.

You can use message.WriteTo("raw-mime.txt") to see what it looks like