Sort by another column error : "We cannot sort the "foo" column by "bar"

I keep hitting this issue trying to sort by another column, where I have many incidents that occur in a single day, my goal is to sort the table first by calendar day, then by the incidents, in the order of most incients counts to least incident counts;

Sample Data;

This is the output I would like:

But I keep getting this error when I sort by another column:

"Sort by Another Column Error"  "We cannot sort the "foo" column by "bar".  You can't have more that one value in "foo" for the same value in "bar".  Choose a different column for sorting or update the data in "bar".