title: skype recieve message not working , getting 403
body: <p>we used this sample to create a bot to respond to images, but from today, the receive image is not working and is giving 403.</p>
  
  <p><a href="https://github.com/Microsoft/BotBuilder-Samples/tree/master/CSharp/core-ReceiveAttachment" rel="nofollow noreferrer">https://github.com/Microsoft/BotBuilder-Samples/tree/master/CSharp/core-ReceiveAttachment</a></p>
  
  <p>It was working till yesterday. Can somebody help here?</p>