If the geometry is completely absent even after these checks, you likely need an Object Enabler matching the source authoring tool (Revit 2023, Civil 3D 2023, etc.).
Use the Autodesk Desktop App (installed with Navisworks) > My Products > Navisworks 2023 > Add-ons. Or try a different browser (Edge/Chrome, not Firefox). If the geometry is completely absent even after