Contact Form 7 shows a verification error when the reCAPTCHA token does not pass Google’s check.
The plugin sends the token to Google’s siteverify endpoint. Google returns a JSON response. If the response indicates failure, the plugin displays the error.
Failure occurs when keys are mismatched, when the domain is not listed in the Google console, or when the server fails to reach Google.
JavaScript issues also stop the token from being generated. Blocked scripts, outdated libraries, or conflicting plugins break the grecaptcha object.
Server restrictions such as firewalls or missing SSL support prevent the verification request from leaving the host.