You probably need a fresh Sync of your data. You can go here and click on the Sync button of the corresponding Ad Account to have the system "check" again for new objects.
An automatic sync is run periodically to keep your list updated (but it's slower!) so if you need to get quick access to a new page this will do the trick!
The Sync will update:
- Custom Audiences list and their status
- Ad Account status
- Pixel and Custom Events
- Pages, Places, Applications and Events
Keep in mind the Sync will NOT update your campaign's stats or import new campaigns!