Georeference tools are greyed out in ArcGIS Pro

Most of the time when I need to use georeferencing tools like 'move' or 'scale' on a raster file (png of historic map), it's greyed out. I've tried all the tips I could find online for this issue, like making sure the rotation for the dataframe is 0 and the coordinate system for the raster layer and map are the same -- no luck. Any ideas?