stats fail only in one domain!

after to move several site from a damage server to a new, i have success in all my webs ( 11 sites), but one, and only one give error when i try to access to stats.
if i remove .htaccess ( from stats folder), i can access and read stats complete, but when i restore .htaccess give error 404. never ask for user/password.
any idea how to rebuild this behavior?
I disable stats, and i re.enabled, i rename everything inside of stats folder. but no change, never ask for login.
i compare main .htaccess to the other site and no difference
maybe .htaccess files has not execute permissions for directory search???
how can i restore???

 

yes, Till
this is .htaccess (web) (attrib 644)

# BEGIN WordPress
# Las directivas (líneas) entre `BEGIN WordPress` y `END WordPress` se generan dinámicamente
# , y solo se deberían modificar mediante filtros de WordPress.
# Cualquier cambio en las directivas que hay entre esos marcadores se sobreescribirán.
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

and this is .htaccess (stats) (attrib 755)

AuthType Basic
AuthName "Members Only"
AuthUserFile /var/www/clients/client3/web2/web/stats/.htpasswd_stats
require valid-user

but (web) are similar to the other site, whats is wrong???

thanks for your time!