Find and fix a vulnerability in user registration on the site

Continuously on the site https://takida.com.ua/ registered a lot of spam users http://prntscr.com/v11edd The site installed the captcha of the latest version of Google. You need to discover how bots get into the site and fix the vulnerability.

Continuously on the site https://takida.com.ua/ registers a lot of spam users http://prntscr.com/v11edd The site is written on ImageCMS. The site has a capcha of the latest version of Google. You need to discover how bots get into the site and fix the vulnerability.