To take an ASP.NET web application offline

1. Create a file called app_offline.htm and put it in the root of your web site.
2. Put a message in app_offline.htm file about web site offline reasons.
3. While the App_offline.htm file exists, content of this file will seen instead of original contents.

After this change, the application domain will restarts.

Important

Remember to remove the app_offline.htm file when your works finished.