An API error (e.g.
An API error (e.g. invalid format response).
Defined in Google Recaptcha documentation, returned by Recaptcha itself, means the captcha was incorrect.
Defined in Google Recaptcha documentation, used by this module, means recaptcha itself couldn't be reached.
The recaptcha response was missing from the request (probably an end user error).
Used to hold various recaptcha error codes. Some are defined by Google Recaptcha, some are used solely by this module. Yes, the Google Recpatcha documentation states not to rely on these, so we deliberately keep these to a minimum.