I have some issues in google search console. My English very poor (sorry). I think will better if you write me any your gmail, I will give access to google serch console, And you will check.
For check this is: for example https://forum.shpargalka.work/human/putin/
All problems come from your hosting and cache plugins. I'm sorry, but I cannot help you solve them, your website is totally crashed by the plugins you currently use. I can only recommend disable all plugins and switch, delete all caches and check your website with wpForo only.
If it doesn't help than this is the theme issue, you should switch to some default theme, keep all other plugins disabled and test wpForo again, so you'll see wpForo doesn't have any issue.
In addition, make sure the forum page is fully excluded from your cache plugins, here is the instruction: https://wpforo.com/community/faq/wpforo-and-cache-plugins/
BTW, I saw the error logs in your another topic, so your website has tons of problems, I'd not recommend developing it further on the hosting service you're now.