It's the same situation.

I've the same problem

We have the same problem. Don't know if it's related but we had a working token, and without us changing anything started getting this error: "Error validating access token: The session has been invalidated because the user changed their password or Facebook has changed the session for security reasons."

Then on trying to generate a new token, nothing happens. Removing the account and trying to re-add it has the same issue, nothing happens on pressing continue, and we just get a console error in our browser.