I deleted a forum earlier this year, its gone from my list of forums and admin can't see it but normal users can see it. I can't delete or change it because it's not there anywhere. I can only see it it if I log in as a normal user and then of course I can't delete or change anything. I hope someone can help with this.
First please navigate to Dashboard > Forums > Dashboard admin page and click on [Delete all caches] button. If it doesn't help you can find that forum in Database using phpMyAdmin tool of your Hosting Service, or installing ARI Adminer – WordPress Database Manager plugin. In database you should open the wp_wpforo_forums table and find that forum.
I've finally deleted it and no one can see it now, it's been there since last Christmas. Thank you so much for your help 🙂