pageofposts stopped working

I implemented pageofposts on our site as a way to categorise the different sections of the site. I created the pages and assigned the custom field according to the relevant categories. The page attributes was set to the pageofposts template and the pages displayed perfectly after publishing.

I decided to change the permalinks to make them more SEO friendly. Once that was done, the pages stopped displaying their posts. And worse than this, the regular pages with posted content stopped displaying as well.

I’ve tried changing back the permalinks to the default. I made sure that mod_rewrite is enabled on our server. I’ve even deleted the pages and created them from scratch. None of this has helped.

Please could someone help.