log in via form autentication :The server could not sign you in. Make sure your user name and password are correct, and then try again.

hi i Configured Forms Based Authentication for SharePoint 2010 now i want to log in via form authentication

but i not log in and faced with this messege

The server could not sign you in. Make sure your user name and password are correct, and then try again.

i followed this link to configured form based authentication.

http://donalconlon.wordpress.com/2010/02/23/configuring-forms-base-authentication-for-sharepoint-2010-using-iis7/

pls help me