Thanks for answer my question. I have the .htaccess file in the directory but I don know if the permissions for the directory and files contained in is 640, user apache and group apache?, when I put a 640 permission, a user and goup different to apache appears :
Forbidden
You don't have permission to access /prueba/ on this server.
when I put a 777 file property all users can see the page, in both cases httpd don't show the user name and password window, mabe one daemon is missing...