I recently started getting a 404 Error when clicking the 'Older Posts' link on the Category page. Clicking the 'More Posts from this Category' link on the Home page does not cause the 404 error. Only when I go a step further and click the 'Older Posts' link within the Category page is when the 404 error occurs.
I have tried disabling all plugins, and also changing the Permalinks Structure back to 'Default' with no success.
The blog is located here:
Here is one of the 'More Posts from Category' links from the Home page:
http://www.thewealthydentist.com/blog/?cat=220 Then click the 'Older Posts' link on the bottom of the page and you will see the 404 Error.
I notice that when I hover over this link it looks fine, but upon clicking it, it adds an extra '/blog/' and also 'index.php', thus causing the 404 error.