I am creating a summary page. I do not want to use a pivot table for several
reasons.

I would like to add all data from Q7:Q9999 (on the "Data" Sheet) only when
the value in AE7:AE9999 (on the "Data" sheet) = C1 (on the "Monthly Summary"
sheet)

This will allow the user to type in a certain Year and month and pull all
credit dollars issued for that month.

Right now I have the below for a formula, but it is not working. Where am I
going wrong?

=SUMIF(Data!Q7:Q9999,Data!AE7:AE9999='Monthly Summary'!C1)

There should be a value to this.