PenciDesign Supporter replied
Hi,
There is some PHP error on your site, so the category page doesn't work correctly. About this issue, please make sure you've installed all required plugins by going to Appearance → Install Plugins. If the error still persists, please disable all plugins you've installed, exclude the plugins that come with PenNews, then re-enable one by one to check the problem.
Regards,
PenciDesign.