Unable to create certain topic

Hello! I am not sure if this issue is not an issue and is done knowingly or not, but it has become annoying. Recently, I have become unable to create topics in many categories. In the category drop-down tab when creating a new topic, only a few of the categories are listed. When I go to view the posts under each specific category, the “New Topic” button is dark grey. I had the ability to post in all categories in the past.

Is this done for a reason or is it a flaw in the Forum system? Thanks!

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