- A website shows an error:
PLESK_ERROR: 503 Service Unavailable
- Application pools crash. Errors like the following one are logged to Event Viewer > Windows Logs > Application:
CONFIG_TEXT: The worker process for application pool 'DefaultAppPool' encountered an error 'Cannot read configuration file due to insufficient permissions
' trying to read configuration data from file '\\?\C:\inetpub\temp\apppools\DefaultAppPool\DefaultAppPool.config', line number '0'. The data field contains the error code.
Process Monitor shows the following:
Insufficient permissions for the application user on the application pool configuration file.
In case one application pool is stopped (an example for DefaultAppPool):
- Login to the server over RDP
- Go to
- Switch to Security tab and Add DefaultAppPool user.
- Set the following permissions and click OK:
In case multiple application pools are stopped:
1. Open C:\inetpub\temp\, do a right-click on the folder appPools > Properties > Security and add read permissions for IIS_IUSRS group:
2. Stop IIS:
C:\> iisreset /stop
3. Remove all IIS applications pools' temporary files and folders. By default, they are located inside
C:\> for /d %p in (C:\inetpub\temp\appPools\*) do rmdir /q /s "%p"
4. Start IIS:
C:\> iisreset /start
The configuration files will be regenerated on a by-demand basis: when a website is opened.