If you're receiving Facebook posting error #200 (Requires either publish_actions permission, or manage_pages and publish_pages as an admin with sufficient administrative permission) and find that your Facebook Group posts are failing, this is due to an update by Facebook in August, 2018.
In order to proceed with posting, you must now give explicit approval to Post Planner as the Group's admin. This is a one time process that will allow Post Planner to post to a Facebook Group on your behalf.
Take the steps below to authorize your Facebook Group:
Refresh Your Facebook Token
a) Login to Post Planner
b) Go to Settings > Social Accounts and click the "Refresh" button next to Facebook
c) Accept all permissions
2. Add Post Planner to Facebook Group Settings
a) Login to your Facebook account and open the Facebook Group you want to activate within Post Planner (this is where you'll give authorization)
b) Select More > Edit Group Settings
c) Scroll down to Apps > Add Apps
d) Type Post Planner in the search field and select it
e) Click the "Add" button
You're all set!
You've completed the one time authorization required by Facebook and now have the ability to post to your Group. The error #200 should stop immediately.