I have no idea why this is happening, but if I'm placing the [wpforo] shortcode on my page, the page can't be loaded anymore. I deactivated already every plugin and my theme, but those weren't the issue. I'm not a pro at something like this, but Firefox is giving those errors: https://ibb.co/9hvLxYw
Forum Basic URL is still basic and i tried it using the test page which wpforo created, so i didn't change anything there
At the Debug page (forum > tools > debug) is only one error: WordPress Email sending function wp_mail() doesn't work!, but i don't think this is doing something or?
The last information: On the wp-admin page is everything working fine, except the Forum > settings > Style & API page are giving an error, too.
If you want the link of the page or something, i can't give it to you, because it's still only local.
EDIT: I even tried reinstalling ...
Please let me know how many pages with [wpforo] shortcode you have.
Have you enabled the mod_rewrite module of Apache?
And do set SEO friendly permalinks in Dashboard > Settings > Permalinks admin page?
Also, please navigate to Dashboard > Forums > Settings > General Tab and click on [Update options] button.
Then delete all caches and check it again.