“There was an error while performing this operation”

Question

I have a website in IIS for which I cannot open any of the settings like Authentication, Handler Mappings, Authorization Rules etc. It just shows the error message \"There was a

Answer 1

It turned out the website was using URL rewrite module which i was missing.

This wasn't my problem and it was. I already had URL Rewriter installed, but after a Windows 10 upgrade IIS wasn't aware of it. A simple repair on Control Panel => Programs and Features => IIS URL Rewrite Module 2 and it was working again.