title: Azure Application Gateway error 502 when using application gateway
body: <p>I followed the docs here <a href="https://docs.microsoft.com/en-us/azure/application-gateway/application-gateway-create-multisite-portal" rel="nofollow noreferrer">https://docs.microsoft.com/en-us/azure/application-gateway/application-gateway-create-multisite-portal</a> but still getting the error :</p>
  
  <p>Azure Application Gateway error 502 - Web server received an invalid response while acting as a gateway or proxy server. There is a problem with the page you are looking for, and it cannot be displayed. When the Web server (while acting as a gateway or proxy) contacted the upstream content server, i</p>
  
  <p>Any help?</p>