Archives organized monthly, but all posts are returned

The plugin organizes posts by month as intended, but by choosing an individual month, all posts are listed instead of the single month.

Is there some additional code I’ll need to place in my archive template?

here is the particular page of the site in question:

https://meta.uoregon.edu/?page_id=36

any help appreciated – thanks!

https://www.ads-software.com/plugins/norman-advanced-archive-widget/