You may have also noticed one of the enhancements we added in last night's release, an in-tool notification that lets you know when you need to reauthorize your publishers. It may look a bit alarming at first, but this enhancement actually makes it very easy to ensure that all pages and accounts are authorized. This will help greatly to prevent failed posts due to lack of authorization.
Simply click the link in the notification and it will take you to the authorization page, where you will need to authorize each page or account individually. There will be a yellow notification warning next to each item that needs authorization, so it is very easy to make sure you've gotten them all. Once everything is authorized all notifications will disappear.
Since there was a new permission that was added last night (see this post for more details) some users may see the reauthorization warning. Please follow the link in the notification and reauthorize as necessary.