How to listen to reCaptchav2 server validation failed event?

https://experienceleague.adobe.com/docs/experience-manager-65/forms/adaptive-forms-basic-authoring/captcha-adaptive-forms.html?lang=en

See this example : 

if (slingRequest.getParameter("numericbox1614079614831").length() >= 5) {
GuideCaptchaValidatorProvider apiProvider = sling.getService(GuideCaptchaValidatorProvider.class);
String formPath = slingRequest.getResource().getPath();
String captchaData = slingRequest.getParameter(GuideConstants.GUIDE_CAPTCHA_DATA);
if (!apiProvider.validateCAPTCHA(formPath, captchaData).isCaptchaValid()){
response.setStatus(400);
return;
}
}