ASP.NET Core application on IIS Express 10 gives HTTP 500 error

I believe I've narrowed this down to a configuration error, but I can't find where the error lies.

Steps to reproduce:

created a new project in Jetbrains Rider 2020.3. ASP.NET Core Web Application, Windows authentication.
let the new project build itself.
try to run the application through IIS Express.

IIS Express starts, but when I navigate to the https://localhost:XXXXX/ page, I get an HTTP 500 error.

Things I've tried:

deleting the applicationhost.config from the .idea folder
deleting the entire .idea folder
deleting the contents of %home%/Documents/IISExpress/config
deleting the %home%/Documents/IISExpress folder and allowing it to rebuild
Reinstalling IIS Express 10
Reinstalling the .NET Core Hosting Bundle

Nothing seems to change the result. This same method works just fine with the IIS Express setup I have at my office, but I can't go there right now. Remoting in is slow enough that it's inconvenient at best, and impractical at worst.

Solution

It would appear that there are some outstanding issues with IIS Express and Rider 2020.3, as can be seen in issue RIDER-55665, though unlike the user here I was unable to fix the problem with the steps provided. It seems as though rolling back from Rider 2020.3 back to 2020.2.x fixes the problem.