bbPress is a forum plugin for WordPress with over 1.5 million downloads. This integration makes it easy for you to add forums to your courses. You can protect the forums so that only users who are enrolled into your courses are able to view content and to post new threads & topics.
Click Here to read the official integration announcement.
Automatic forum access: As soon as someone purchases (or registers) for a course, they are granted forum access so that they can create new threads and topics.
Public or private forums: Allow visitors to see forum topics or block the forum contents entirely so they are exclusive for your enrolled users.
Multi-forum support: Associate as many forums as you want to your course.
Custom “Access Denied” messages: Inform users how they can get access and even send them to a sales page.
Dynamic associated forum widget: Place this widget in your course sidebar and it will dynamically display the associated forums for the course. Users can click on the associated forum name to be taken to the forum itself for posting.