cannot access files in trash previously on external harddrive
The drive-wide Trash contains the deleted files of all users, with one directory per numerical User ID. Run
ls -l /Volumes/edrive/.Trashes

to see that 503 is a directory, and
ls -l /Volumes/edrive/.Trashes/503

to see its content.
PS: You can see your own user id by running id -u . If it is not 503 you'll need to run sudo ls -l /Volumes/edrive/.Trashes/503 instead.