Sum for 3 month and a year

Hi everyone,

I have a dataset for reporting service which contains statuses of items for various periods of time.

I have two columns, one for 3 months and other for year, so I tried using to count items with respect to date:

However, my report doesn't render, unless I remove month part. How I can count for 3 month?

I've also tried adding different datasets for 3 months and year, however, lookup function doesn't work for IIF. Is there any other way?

Regards,

Yerkhan