enable Joomla captcha

Hi - I enable the Joomla Captcha in the User Management Area. The plugin also is enabled with the public/private keys (from google).
But the MP registration page still gives me an error that it needed enabled. What am i missing.

Thanks,

Maybe go to System -> Global Configuration, in the Default Captcha, set it to reCaptcha (or the captcha plugin you want to use)

After that, it should work as expected

Tuan