Error Shortcode

Hi!
I’ve embedded the shortcode for sweet captcha to my theme template and works well. However, there is no error message should a guest registering try to skip the captcha. So page gets reloaded without submission, and its stuck on captcha step. Anyone know of a solution to get the error message if skipping?

<?php echo sweetcaptcha_shortcode(); ?>

Thanks

https://www.ads-software.com/plugins/sweetcaptcha-revolutionary-free-captcha-service/