Google reCAPTCHA is a free service that must be added to protect your site from spam and abuse. It uses advanced risk analysis techniques to tell humans and bots apart.
Use this link to get your Site and Secret Key:
Click the + icon in the upper right hand corner.
In the Label field add your custom URL.
Select reCAPTCHA V2 - I'm not a robot Checkbox
In the Domains field, add your registered domain name, accept T&C.
A new page will open revealing the Site and Secret Keys.
Copy and Paste these into the fields under Google ReCAPTCHA Key in your SubHub control panel Site Settings > Integrations. Click Save.