There is a known issue where if a student copies and pastes bad HTML code into their post, the discussion board will break and the Start a New Thread and Reply to Thread buttons will no longer be clickable. Specifically if they copy in <div> tags.
To fix this issue:
- Go to the affected course
- Go to Edit Course>Discussion>Access Faulty Discussion Topic
- Switch to Grid View
- Manually check each and every students post by accessing them one by one
- For example, Consider accessing one students post, Click on it
- Go to Edit Post, In the Edit Post page under post(HTML Editor) go to The HTML Source editor(</>)
- Look for <div> tags, If present remove them by leaving only the <p> tags with the content and click save
- If not present then go to another students post and follow steps from 6-7 until you find the faulty post
Start with the post you think is bad.