Permalinks Blog Problem

Hey, i got a website with a blog which has 4 different categories
when i use the default permalinks everything works fine and the posts are published and shown on their own categories, but when i change it to a different type, let’s say “Post name” all the posts are shown on every category. That’s my .HTACCESS.

# BEGIN WordPress

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress