.htacces error

Hi, I have a list of pictures by categories (List & Detail) but apparently the .htaccess file is not working as it should and that the page does not exist: "Not Found The requested URL /category/stock/news/ was not found on this server" but whether there are pages (category.php...). Thanks in advance.

<IfModule mod_rewrite.c>
Options -Indexes
RewriteEngine on
RewriteBase /
RewriteRule ^photo/([a-zA-Z0-9-/]+)$ /photo.php?s=$1 [L] 
RewriteRule ^category/([a-zA-Z0-9-/]+)$ /category.php?cat=$1 [L]
RewriteRule ^gallery/([a-zA-Z0-9-/]+)$ /gallery.php?s=$1 [L] 
RewriteRule ^gallerycat/([a-zA-Z0-9-/]+)$ /gallerycat.php?cat=$1 [L]


# Redirect to PHP if it exists.
# e.g. example.com/foo will display the contents of example.com/foo.php

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}.php -f
RewriteRule ^(.+)$ $1.php [L,QSA]

</IfModule>