Captcha login issues

Hi ppl,

I tried to setup captcha for a new login page in F5 APM. I have registered the site successfully in the google.com/recaptcha. When I try to access the url, I get the login page with the captcha screen displaying on it. But When i type my username(which is valid) and type the captcha that is displayed in my screen and hit logon button. It gives me error saying"Data provided for authentication is not valid. Please try again." Am not using any authentication server to lookup the username, its just a fallback set to the access policy flow. Not sure how to make this work. please advise me on setting this up successfully.

Thanks Balaji Thangarajan