reCAPTCHA v3 doesn’t ask visitors to do anything. Google gives each one a score from 0.0 (very likely a bot) to 1.0 (very likely a person), and the reCAPTCHA addon turns away anyone below the required score. The required score is 0.5, Google’s own default.
If real users see “Recaptcha validation failed” when they log in or register, Google is scoring them below 0.5. First check that your keys are v3 (score-based) keys and that Users > Settings > General > reCAPTCHA is set to Version 3. If they are, lower the required score.
Lower the required score
The wpum_recaptcha_score_threshold filter sets the score. Add this to a code snippets plugin, or to a file in wp-content/mu-plugins/:
add_filter( 'wpum_recaptcha_score_threshold', function () {
return 0.3;
} );
Start at 0.3 and lower it in small steps only if people are still blocked. The lower the score, the more bots get through.
If it keeps happening
Some visitors, such as people on VPNs or strict privacy settings, score low however you tune it. If that’s your audience, switch to Version 2 with the Checkbox type: a doubtful visitor gets a puzzle to solve instead of an error. It needs a checkbox key, see Generate reCAPTCHA API keys.
Google explains how scores work in its reCAPTCHA v3 documentation.
Get Started with the Best WordPress Membership Plugin Today
Connect, Manage and Build your Membership Site