Now, I do block pretty much everything by default (JS, etc.) but even after allowing everything, and several full refreshes of the page, I never could get the captcha to show up. Problem might be on my end, but I can almost always get a web page to work, once I allow enough stuff.
It’s a Google Recaptcha. Does this normally work for you?
I’d love to use some other captcha, but I don’t have the time to implement one for NodeBB. The last time I have looked there was only a non-working math captcha plugin for NodeBB 😞