By default, a News Forum in a Moodle course will allow posts and replies to only be added to it by teachers on that course.
This can be overridden to allow students to reply to posts.
- Within the news forum in question, click on the Permissions link in the Settings block.
- Find the relevant activity (e.g. Reply to news) and click on the plus icon underneath the list of users to amend permissions.
- Check the permission change information that is displayed, use the dropdown list to Select role as 'Student' and click on Allow to confirm the change.