hangs when clicking "Add file"

Dear folks,

When clicking the “Add file” button right on, the page hangs indefinitely. I tried Microsoft Edge and Internet explorer, it makes no difference. I don’t know anything about web development, I have no idea how I could debug this and provide additional information.

I can only see in my task manager that one CPU core is entirely being used by my browser.

In case it helps:

Microsoft Edge 42.17134.1.0
Microsoft EdgeHTML 17.17134

Internet Explorer 11.0.85

How can I find out what is causing this and how to fix this?

Please try chrome for Firefox , IE has the history of getting hung up 

Unfortunately, I cannot install random browsers on my work machine. I have never had IE hang up on any site. Edge also had the same problem on