Printful Products and In House Products not allowed to checkout together

Hi all, we just started adding products to our store with Printful, mainly shirts and hoodies. We also sale hats out of our office because Printful doesn’t make the hats we like. I was doing some testing before our store goes live and when I put a product from Printful in a cart with a product from our office it won’t let me check out saying “There is no shipping option available for your items”. If I take out one or the other and try to check out it works just fine. Has anyone encountered this?