A slightly less obvious error encountered while using IIS on a specific site, where all pages give the following error: HTTP Error 500.19 - Internal Server Error The requested page cannot be accessed because the related configuration data for the page is invalid.
So exactly how do I setup a 404 error page on my site? It's good practice to use 404 error pages on your site instead of relying upon the built in IIS error handling mechanism and it's not that obvious how to set it up.
How to add HTML5 MIME types to IIS configuration to resolve HTTP error 404.3 file not found.
Lets Encrypt offer a free SSL service, but configuring a server to allow non-HTTPs access to the .well-known, while also redirecting all other non-HTTPs requests can be tricky. Luckily IIS allows a neat way this can be achieved with Web.config redirects, here is how!