Everything worked correctly on my IIS, but I installed Windows Fall Creators Update and everything stopped working.
I get an 503 - Service Unavailable error on every app and page inside my AppPool I visit. I've checked the Windows event viewer and it says the following:
I've searched among the web and none of the solutions work (permissions, credentials...). I've even uninstalled completely IIS (with WAS included) and reinstalled it to reset to its factory settings. All my applications now are gone (as expected), but I still get the same error.
My system is a Windows 10 Pro (version 1709) Lenovo laptop. No updates are available on Windows Update.
More information of the error on Event Viewer:
What's wrong with my IIS configuration and how can I make it to work again?