How to send an email through a Proxyserver

[Lukezzz]

Hello,

I wonder how it works when you want to send an email through a proxy server.
I have code below that works if you want to send an email through for example smtp.gmail.com etc.

I have put the proxyserver address and port that the proxyserver has as the 2 arguments below.
However when I try to run the code the sending fails.

So my question is how it is possible to send an email using a proxyserver like this ?

using System.Net.Mail;

String^ Proxyserver = "210.212.85.146";   
int port = 1080;             
  
  
MailAddress^ to = gcnew MailAddress("[e-mail]");   
MailAddress^ from = gcnew MailAddress("[e-mail]");   
MailMessage^ message = gcnew MailMessage(from, to);    
  
  
message->Subject = "Hello1";   
message->Body = "Hello2";   
  
SmtpClient^ smtp = gcnew SmtpClient(Proxyserver, port);   
NetworkCredential^ NetworkCred = gcnew NetworkCredential();   
NetworkCred->UserName = "[e-mail]";   
NetworkCred->Password = "passWord";   
smtp->Credentials = NetworkCred;   
  
  
try  
{   
    smtp->Send(message);   
}   
catch (Exception^ ex)   
{   
    //Failed   
}