Need help with reCAPTCHA - keep getting incorrect-captcha-sol

Question

I am trying to add a reCAPTCHA to my site, but keep getting incorrect-captcha-sol error when I submit the answer.

Can anyone tell me if I am correct in

Answer 1

if you are posting the check twice - eg once from javascript and once via php the second one will fail as the API only allows a solution to return valid once.

Hope that helps, Josh