Facebook is changing things again. On December 5th, one of the features I rely on for Facebook Logins is going away. You may find that you login sessions expire randomly. If so, just log back in. At present I don't know how long login sessions will last. It may be as little as 2 hours.

I'm dealing with this change from Facebook in the new code I'm working on now.

This is one of the downsides of relying on third parties. They always change things at random for no apparently good reasons.