Problem with Category page

Hi,

Just launched a new blog last night

https://www.theaestheticpoetic.com

Everything is running smoothly for the most part but I am having one problem with the category pages.

If you pick to display a category

https://www.theaestheticpoetic.com/?cat=41

The first page displays fine, but when you click NEXT PAGE at the bottom, the page blows apart.

I am sure I have overlooked something simple here but I am not sure what.

Any help is much appreciated!