Getting 404 errors on my categories and posts.

My website anime reviewed is having some problems. The posts and categories when i click into them give 404 errors. I checked my htaccess and it contains this:

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

I have also checked to see if any of our plugins were causing a problem. We deactivated anything related to the permalinks.

any suggestions would be appreciated.