Archive widget won’t sort blogs when month is clicked

Thank you for a great template. The cleanliness and simplicity make it a favorite of mine.

My client’s start-up website is https://www.PremierEndpoint.com

Our issue happens when clicking on a month in the Archive widget, it fails to sort the blogs. It simply returns all of the blogs starting with the most recent. For example, clicking on September does not show only September, but shows all, starting with the most recent.

Any suggestions would be greatly appreciated.
Thank you!