I see such texts in your page content. What is this??
>REGISTRATION ATTEMPT BLOCKED</strong>: This site requires a security token created when the page loads for all registration attempts. Please ensure JavaScript is enabled and try again.
wpForo doesn't have such things in the registration form. Are you using custom scripts or plugins to protect your registration form? Please find and remove all.
Search in functions.php file of current active WP theme, search in /wpforo/ folder in the WP active theme, you may have customized WP template files. Search in plugins and remove all registration protecting plugins.
So wpForo registration for is crashed by some plugin or script, we cannot help you fix this issue, this is not wpForo issue, you should find the conflict maker and disable it.
Interesting. I'm not seeing that text at all. Even if I don't check the recaptcha box.
Any chance you didn't click the box before submitting?
Are you running, Wordfence?