I Ilooked on my forums and the category for the 2nd forum is
[wpforo item="forum" id="17"]
he 3rd is
[wpforo item="forum" id="1"]
So that should be fine. But the pages are blank
Not Blank but 404.
Please never duplicate topics in support forum. Next time we have to ban your account.
As per the issue, please make sure the pages you're using for shortcodes are not a child pages of forum page. Forum page should not have any child pages.