When logging on to the WebUI, a user may receive the error “Service Unavailable” message with the specific code "HTTP Error 503. The Service is unavailable.
There can be a couple of different issues when this error is generated.
1 - The PrognosisAppPool Application pool in Internet Information Services (IIS) has stopped and will need started. To start, open IIS and drill down to your server name, then click on "Application Pools". Check the status of the PrognosisAppPool application pool. This needs to be running for the Prognosis web interface to work properly,
Right click on the PrognosisAppPool name and and select start and it should go to a Started staus.
2 - If starting the PrognosisAppPool application pool does not keep the Web UI accessible, then you will need to check the application events and filtering on the "IIS-W3SVC-WP“ source. Look for any errors. You may see something similar to the below.
In this instance, a DLL file failed to load. In your case, it might reference another dll file. You would then need to find the application that installed the dll and troubleshoot the application or uninstall it as it is causing problems with the web interface of you dedicated Prognosis server.
Once you address the issue with the offending dll file, start the PrognosisAppPool, application pool and it should start.