Help with SumIfs

Hello! I'm looking for some help with SUMIFS please 🙂 

I'm trying to show on the table on the right to total number of resource required per month per resource type. For example, under January and Project, this should say 1, and for May and Project it should say 2.5 etc.

I'm currently using SUMIFS(D8:D41,B8:B41,N7,D8:D41,D7=O6) and I'm getting an error. 

I'm sorry if this seems easy to fix, but I'm struggling to understand what this won't work? Any help is greatly appreciated 🙂