title: how check a validated Email Exist Or Not Without Sending test Email by c# codes?
body: <p>how can we check that a <strong>validated</strong> Email exist Or Not Without Sending test Email by c# codes?<br>
  we can check Validation of that email by many ways...<br>
  but what about existence?<br>
  is it possible to do that or not ?  </p>
  
  <p>thanks in advance</p>