Ontology for a Semantic Model

Has anyone had any trouble creating the ontology for a Power BI Semantic model? I've gone through all my tenant settings and enabled them for my BI admin group/user. But I'm still getting the error code: PowerBIFeatureDisabled. I have an F128 premium capacity. I'm pretty sure I've checked all the boxes but I still can't generate an ontology. Does anyone have any suggestions?