Question: Plesk and sites show: HTTP error 503 - Application Request Routing\requestRouter.dll failed to load
Symptoms- Websites are not accessible with HTTP error 503
- PleskControlPanel and most IIS application pools could not be started at IIS > Application Pools.
- Event Viewer > Application log contains the following error under Event ID 2280
The Module DLL C:\Program Files (x86)\IIS\Application Request Routing\requestRouter.dll failed to load. The data is the error.CauseMicrosoft Application Request Routing package corrupted or missing.
ResolutionDownload and install Application Request Routing package from Microsoft website: