How do I solve this problem that AcuSolve won't use my mesh?

I am currently trying to simulate air flow through an accumulator and I set up where the air flow is simply entering one side and exiting the other. I used essentially the default CFD Mesh, only inputting the element sizes. I also used the whole body as a fluid body(not sure if it makes sense to do that). However when I went to solve the flow, I get the message "AcuSolve export is supported only for volume mesh bodies." I attached it in the photo, what does it mean and how can I get past it?