Incompatibility data in pivot table

Hello, 

I'm doing a data studio with a Pivot Table with a google ads by supermetrics source.

I'm putting "brand" on row dimension; "month and year" in column dimension; and cost in Metric, and data studio says "Incompatible fields"

I tried differents combinations, and if I take "brand" off, and i replace by "campaing name", that's correct and I can see all datas in the Pivot Table.

There is any incompability between brand and cost ?

Thank you

Ana