- Plesk 11.x for Linux
- Plesk 11.x for Windows
- Plesk 12.0 for Windows
Error "HTTP Error 503. The service is unavailable" appears while opening Plesk.
The following error is in Windows Event Viewer > System log:
CONFIG_TEXT: Application pool 'DefaultAppPool' is being automatically disabled due to a series of failures in the process(es) serving that application pool.
And the following error is in Windows Event Viewer > Application log:
CONFIG_TEXT: The Module DLL 'C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\15\isapi\spnativerequestmodule.dll' could not be loaded due to a configuration problem. The current configuration only supports loading images built for a x86 processor architecture. The data field contains the error number. To learn more about this issue, including how to troubleshooting this kind of processor architecture mismatch error, see http://go.microsoft.com/fwlink/?LinkId=29349.
Plesk application pool is working in 32-bit mode. Global (i.e. applied to all application sites on all application pools) ISAPI module
(SharePoint 2013 and 2016) is a 64-bit application. Attempt to load 64-bit application on 32-bit application pool is not possible, which causes application pool to fail on start-up.
To apply the solution from this article it is required to have RDP access to the server. Please contact your hosting provider support or server's administrator if you don't have RDP access or ask them to apply the solution.
IIS 7.x can load global ISAPI modules conditionally, depending on the application pool's settings:
- Connect to the server via RDP.
Open Command Prompt ( Start > Run > cmd.exe ).
Type this command:
C:\> %systemroot%\system32\inetsrv\AppCmd.exe set config -section:system.webServer/globalModules /[name='SPNativeRequestModule'].preCondition:integratedMode,bitness64
- Restart Plesk Management service using Plesk Services Monitor .