Permalink Category Issues

Hi

I have a blog which uses a category/subcategory/postname structure. Viewing posts via the domain/parentcategory/ and domain/parentcategory/subcategory/ work fine.

Links going directly to a specific post present me with a 404 error, i.e. domain/parentcategory/subcategory/postname/

The content of my .htaccess

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

My permalink structure:

/%category%/%postname%/

I’ve tried deleting and rebuilding the htaccess file and resetting the permalink structure to default/re-submitting the permalink structure but I’m presented with the same error.

I’ve also tried using different templates including the default one but to avail.

Does anyone have suggestions?

Thanks