Not delete foldre on my EX2100

Hello,
I have a problem to delete folder on the directory named public on my WD EX2100 server.

These directories were created during a direct copy by connecting an external drive to the port on the front panel and pressing the Copy button above.

I managed to remove the files they contained but not directories, the server tells me that I need permission from / WDMYCLOUDEX2100 / nobody to delete these directories.

How do I delete these empty directory?

Thank’s

You need to go in via the admin access, and you must be the admin.