Captcha not blocking when stamp is missing

Hello Matthias,

I am trying to get this plugin working, but it doesn’t seem to be blocking when the stamp is missing. I followed the video tutorial, and set up a pattern for a simple WordPress comment submission: {“comment”:null,”submit”:null}. The pattern seems to be working, because after setting it up, form submissions are shown in the Messages table instead of the Analytics Box table. From this point, I expect the plugin to block any request that does not have the stamp, for example when I send requests with JavaScript disabled or with cURL. This is not the case, as these requests are also accepted, processed and shown in the Messages table. When using the Simulate spam messages mode, everything is blocked as intended.

I have no other plugins enabled, and I am using the default Twenty Twenty-Five template. I checked the Block spam checkbox. I have no whitelisted IPs or sites and no hidden actions or patterns set.

Thank you in advance,
Ádám