Upgrading broken my integration

I believe latest Facebook updates in API broken the integration, my gallery doesn't work, although in the backend it says it is connected.

When I go to refresh user access token it just pops up a blank window, and below that window the loading animation just continues.

This is a live event website, it needs to be integrated with Facebook, it's becoming embarassing for me with my clients.

Can you assist in any way possible please?