The sign-up or registration page is a prime target for hackers, spammers, and brute force attacks. One way to avoid these attacks is by using reCAPTCHA which effectively blocks spambots and protects the site from being hacked.
To enable the reCAPTCHA V2 from Google, create or use an existing google account and follow the instructions given here to generate a Site Key: https://developers.google.com/recaptcha/docs/settings
Parameters are to be set in the SAP Business Transformation Platform Cockpit (SAP BTP Cockpit):
Note: The sitekey differs for every individual. Screenshot above is for reference only. Please use the unique sitekey generated during your setup using your own google account.
Once the setup is completed, self-registrants will be required to pass reCAPTCHA validation on the sign-up page like below: