Wordpress blog index issue with pagination

I have a Wordpress website and i have set my Posts to show on a particular url, eg /blog. It shows results on the initial [login to view URL] page, but as soon as i click my pagination links to view results on page 2 or 3 etc it says in the Meta Title "Page Not Found". BUT, if i choose a Category first, then click the pagination links, they all works fine, eg it DOES display posts on page 2 etc. So the problem is ONLY on the [login to view URL] page. My permalinks are set to Month and Name. In Permalinks the Category Base is set to 'blog' as well as the Tag Base is set to 'blog'. The loop code in [login to view URL], [login to view URL] and [login to view URL] is this : <?php if (have_posts()) : while (have_posts()) : the_post(); ?> <?php the_title();?> <?php endwhile; ?> <?php else : ?> <?php endif; ?>