SOCIAL experiences are compatible with Chrome 56 onwards (released 2017).

On Chrome, you can reset permissions using a dialog on the left side of the address bar. Click on the camera icon as shown below.

You'll see that the camera and mic are both blocked.

Use the drop-down menus to select "allow" for each. Then close the dialogue using the cross at the top.

Your browser will ask you to reload the page. Once you've done that, you should be able to log in to your SOCIAL experience.

If you need to switch which camera or mic you're using, see instructions here.