Excel 2021 Pivot Table "Show Items with no data on rows" is greyed out

Hi

I am creating a report where I am using two different pivot tables based on the same data but with different filters applied to each of the two pivot tables. This is creating tables which are not the same dimensions. Both tables are showing day on the column and year on the rows. After the filter is applied, table 1 may have all years showing but table 2 has 2017 and 2019 missing. This is because there is no data for years 2017 and 2019 after the filter is applied for table 2. This is expected. However, when I want to do a calculation that involves both tables, I cannot easily match up the cell entries because table 2 is missing years (2017 and 2019). I need table 2 to show years 2017 and 2019 even if all the values are zero. I thought that the "Show Items with no data on rows" option would help but it is greyed out. How do I make it available so I can test my theory that it works or not?

Thank you