ReCaptchaV2 not working – ‘Unknown captcha error!’

Hi,

so I included a recaptcha button in my form using the

RecaptchaV2

option and adding the site and secure key (generated by google) in the

‘Google ReCaptcha Site Key’

and

‘Google ReCaptcha Secret Key’

settings field.

I can click the button and it gets green, but when I submit the form the button shows:

“Unknown Captcha error!”

When I use the

RecaptchaV1

it works.

Do you have any idea what the problem could be?

Thanks for the nice plugin!

Cheers,
Martin