Do you remember clicking "Choose what you allow" when connecting your Facebook Profile? If so, you may have limited our access to some permissions for individual Facebook Pages or Groups by unchecking them.
Fixing this is done via the Facebook Settings, at https://www.facebook.com/settings?tab=business_tools. Find our application in the list there (it may have a different name depending which company you're with - send us a support message if you're not sure!) - and click "Edit Settings".
On the resulting screen, if you see the small blue "Pages" or "Groups" links on the right-hand side, you have limited our access to certain Pages or Groups.
Click each "Pages" or "Groups" link, and make sure the Page or Group in question is checked. If it isn't, check it and save your settings.