title: How do I show "Down for maintenance" for site hosted behind Application gateway
body: <p>We have a website hosted behind  Azure Application gateway load balancer. When we take site down for maintenance it shows 502 error to end users, which isn't nice. Even if we put App_offline.htm, it shows 502. </p>
  
  <p>Any other way by which this can be done?
  Thanks in advance.</p>