Unable to publish changes to FB Chat widget

The Facebook Chat widget was operating as it should and I was able to edit it and publish it as required. All of a sudden, I find that when I go to publish any changes, I get a message saying it only “Page Admins can make changes” when I am, in fact, a Page Admin. My WordPress site has been white-listed in the Advanced Messaging part of the Facebook New Pages Experience. I am hoping to use this widget and so would really appreciate assistance in overcoming this problem.

The page I need help with: [log in to see the link]