Description
Some detail features were not imported. These features may represent complex or unsupported geometries for the target Indoors workspace. The message includes a list of the Ext ID values of the details that were not imported. Inspect the features that were skipped by adding the Floorplan_polyline layer from the BIM file to a map and locating the features with the listed Ext IDs.
Solution
Try running the tool again using a different type of Indoors workspace. For example, some geometries that are unsupported when importing to a hosted feature layer can be imported to a file geodatabase.