Hey Rene,
Actually that "Renew button" do not function anything, I will discuss with the team whether we need to remove this in the next version.
If your Facebook token already expired, what you need to do is just need to click on "Revoke button" then re-authenticate again with your Facebook user account.
If the issue still persists, perhaps you can share with what happen when you click on "Sign in via Facebook" button?