Sum showing zero

I have a report which was not showing the sum on a groups that were formulas.

I am now at a point where I have created a "bare bones" report, with just 1 group which is not a formula, but just a simple field.

I created a group on this field, and put a summary total of an amount field in the header and the footer of this group.

However, Crystal shows "0" on both sums. Why?

As a way of troubleshooting, I added a different aggregate, a "count" , and put it in both header and footer.

The count does show in the footer, but not the header.

What could be wrong?