title: What can cause "The specified string is not in the form required for an e-mail address"?
body: <p>What can cause the error "The specified string is not in the form required for an e-mail address"?</p>
  
  <p>Source code line that causes the error:</p>
  
  <pre><code>msg.To.Add(new MailAddress("txtEmail.Text"));
  </code></pre>