This layer is a dimension feature class, which cannot be edited with an ArcGIS Desktop Basic license.
Solution: Upgrade your license to ArcGIS Desktop Standard or ArcGIS Desktop Advanced.
Warning: Not licensed to edit dimensions
ArcGIS Desktop is in mature support and will be retired March 1, 2026. There are no plans for future releases of ArcGIS Desktop, and it is recommended that you migrate to ArcGIS Pro. See Migrate from ArcMap to ArcGIS Pro for more information.