Thanks for answer. Yes, it’s about WPForo you linked above.
Most of the forums system works nice with WPArmour, but adding posts or comments (replies) cause issues – it’s blocked by this addon. It’s not very irritating, but it does bother and surprise users. The solution can always be an option in the plugin to bypass a specific link and everything related to it – for example /forum as user still must use login/register form that is protected ??