Problem with External Storage (HDD) ¿Permissions?

Hi.

We deploy NextCloud on Ubuntu Server VM storing the files in external storage (Icy Box).
Everything is OK aparently, we see the storage correctly and we can create folders inside with the created users.
The problem is the “unknow issue” when we try to delete a simple folder, wich folder was created by the same users that intent to delete…

I show you some pictures but if you need some pictures to try to help me I will provide you them.


thanks in advanced.

another image here because it doesn’t fit in the first post.

permissions