Multiple List as Subsites

I am trying to follow your example in the below https://plumsail.com/sharepoint-dashboard-designer/documentation/use-multiple-lists-dashboard-designer/
I am not getting anything in the aggregation field.
I have followed your example excatly
I have a site collection called Programs
with a list called projects
I have the below information Title and URL
with the URL being the URL of the subsite
MATH and science
/sites/programreview/Math
/sites/programreview/Science
with task list
called “Task List”
In each
then I paste your code but nothing comes up in aggregation.
We are demoing this product and need this to work to see if it will work for our needs
Thanks

Dear Jennifer,
This is SharePoint Online, correct? The best that we can offer is to take a look at it ourselves since there is a lot of things that we’ll need to check to make sure everything is configured correctly in relation to the lists. Providing temporary access to the site might be the best solution.

You can email us with details at support@plumsail.com

Nikita,
This is actually on Prem but I will email you at support