Service Application Unavailable IIS7
There are many things that cause this. read here For more detail and accurate step.a
Check Security, already There.
See the Log of IIS on C:\inetpub\logs\LogFiles\W3SVC1, the request return http error code 500. Not much Help
Do a ‘appcmd list appppools’
Nothing wrong on the application pool. No Crash
See the Event Viewer –> Application.
There’s a Information:
A request mapped to aspnet_isapi.dll was made within an application pool running in Integrated .NET mode. Aspnet_isapi.dll can only be used when running in Classic .NET mode. Please either specify preCondition="ISAPImode" on the handler mapping to make it run only in application pools running in Classic .NET mode, or move the application to another
Aha, my application still calling the old Way Isapi.
Change the ApplicationPool Mode to Classic
Bingo!