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

Are you sure you are typing in correct words?

this one is from recaptcha website :

Line 1       "true" or "false". True if the reCAPTCHA was successful
Line 2  if Line 1 is false, then this string will be an error code. reCAPTCHA can 
    display the error to the user (through the error parameter of api.recaptcha.net/challenge).
     Implementations should not depend on error code names, 
as they may change in the future.


    Example: If your response looks like this:

    false
    **incorrect-captcha-sol**

    ... you can add '&error=incorrect-captcha-sol' to the challenge request URL, 
and the user will get an error code.