Getting site under construction message after azure webapp deployment

I resolved my issue. Solution was to remove offline html (APP_OFFLINE.html) from root directory(on server) that is created because of the app offline rule i added to publish profile.

actual problem : <EnableMSDeployAppOffline>true</EnableMSDeployAppOffline> in your publish profile that is actually used to take your app offline while deploying. After finishing deployment, MSDeploy tool should delete APP_OFFLINE.html automatically. But, somehow it did not happened in above case.

So what I suggest is, take a look at the root directory of your website and if there's a file called APP_OFFLINE.html, just remove that.

Culprit for this outage : app_offline.htm

This is a known bug with Azure Kudu service where it fails intermittently to delete app_offline.htm file from the server - https://github.com/projectkudu/kudu/issues/2949.

This file gets added to bring the site down temporarily and should be removed once the site is upgraded. But this is not happening consistently. As of Nov 2019, the bug is still open.

There is a simple work around for this :

• Open your app service in Azure. On left hand panel, scroll and find Advanced Tools. Click Go. This will take you to Kudu service for your app service.
• On the nav bar, click Tools > Zip push deploy.
• There will be a file app_offline.htm in the list.
• Click on delete button left to it and delete it. That's it! Your app should be up now.

Permanent Solution would be :

Tell Kudu not to create this file at all by adding key SCM_CREATE_APP_OFFLINE with value 0 in your appsettings.