Hello,
I think you could check following configurations:
1. Whether your hierarchy is assigned to the application “Product”
IMG Path:Cross Application Component -> SAP Product -> Product without customizing transfer from backend system -> Assign Category Hierarchies to Applications
2. Whether you assign product type "Material" and corresponding object family to your categories
IMG Path: Cross Application Component -> SAP Product -> Product without customizing transfer from backend system -> Maintain
Categories/Hierarchies
Regards,
Maggie