%windir%\system32\inetsrv\appcmd set config -section:asp -scriptErrorSentToBrowser:true
Ewentualnie dodatkowo:
%windir%\system32\inetsrv\appcmd.exe set config -section:system.webServer/httpErrors -errorMode:Detailed
lub w pliku web.config w gałęzi system.webServer dodać:
<httpErrors existingResponse="PassThrough" />