Error on captcha

Hi Guys,
i’m using gravity form to build this form, i’ve also registered this CAPTCHA with Google and have enter the site Site (Public) Key: and Secret (Private) Key in e.g

when i view the form url:( https://wp.architecture.com.au/sandbox/form/ )
i keep on getting this error message “ERROR: Invalid domain for site key in the captcha”

e.g https://wp.architecture.com.au/sandbox/wp-content/uploads/sites/3/2015/04/error.jpg

any advice on what can be wrong?

Thanks

https://www.ads-software.com/plugins/gravity-forms-no-captcha-recaptcha/