Application pool has been disabled

problem ：
Application pool DefaultAppPool Has been disabled .Windows Process Activation Service (WAS)

If your application pool is running as a specific identity , The expired password may be the cause of your problem .
Solution steps ：

1. The computer management office resets the password
   
   2. Reset the password of the identity at the advanced settings of the application pool , Password is managed by computer -> Set at local users and groups .
   
   
   
   The fundamental solution ： Set the password expiration policy to never expire , Otherwise, after the password expires for a period of time , The application pool will be disabled again , Then go to reset the password. It's still troublesome .