FTP upload failure from 2 clients

Hi,

I am second time trying to upload something to OMV 6 ftps.
No success. Both Total Commander and FileZilla do not have permission, but I can not catch where.

Zilla:

Command:    STOR 72879-771436(1).pdf
Response:    550 72879-771436(1).pdf: Operation not permitted
Error:    Critical file transfer error

Ghistler:



At which point I should start digging acorns with a snout?