I did visit the page. However, none of the questions I raised were answered (or answerable) from doing that. So, I assume from your comment that you enabled and configured the plugin and have valid credentials that you entered in the plugin config. That does not answer the questions about the webserver settings or your logs, though. Also, are you using ReCAPTCHA v2 or v3? IIRC the plugin doesn't work with v3.