title: Why i get Wrong file identifier/HTTP URL specified error in telegram bot?
body: <p>I'm new in telegram bot and try to send photo to user with this code:<br/></p>
  
  <pre><code>await Bot.SendPhotoAsync(update.Message.Chat.Id, "http://182.126.201.42/" + "iisstart" + ".png");
  </code></pre>
  
  <p><br/>
  but when i try run that code,get this error:<br/></p>
  
  <pre><code>Bad Request: Wrong file identifier/HTTP URL specified
  </code></pre>
  
  <p><br/>
  How can i solve that problem?thanks.</p>