Unable to restart subscription Application Pool via Plesk GUI if application pool is already stopped in IIS.
Internal error: websrvmng failed: The service has not been started. (Exception from HRESULT: 0x80070426) In Microsoft.Web.Administration module Exception type: System.Runtime.InteropServices.COMException at Microsoft.Web.Administration.Interop.IAppHostMethodInstance.Execute() at Microsoft.Web.Administration.ApplicationPool.Stop() at IIS7ApplicationPool.startStop(IIS7ApplicationPool* , Boolean start) at IIS7ApplicationPool.stop(IIS7ApplicationPool* ) (Error code 1)
The error was displayed when application pool had already stopped in IIS. This behaviour has been fixed since Parallels Plesk 12.0.18 MU#30
Start web site or an application pool manually from IIS. Apply the latest Plesk update.