When you go to post in some sections it just redirects you to the index. And its only in certain forums. I searched but I cant find an answer.
We don't know an answer without any details either..
1. What's your board URL? A testing account would be nice too.
2. What's your MyBB version?
3. Provide the result of ACP -> Tools & Maintenance -> File Verification
4. Provide the list of plugins used by you.
Figured it out after looking at what forums were buggy. It was a plugin that allowed me to set a default message for forums. I just dint think about it until now.