Favicon issue

Heya,

I have some issues adding my favicon to the site. I go to Customize and when I try to add my Favicon.ico in the menu General – Upload your favicon, nothing happens. It won’t upload or pop up.
Do I need to manually put the file in the root of my site or do I have to use a custom plugin for this, should it be in any other format than .ico?

Thankful for any answers out there, keep being awesome!