Don't have permissions on Samba USB Disk

Hi,
I just installed samba from App Store and I can see on my Mac computer the OSMC with the USB disk connected. I can connect and navigate, see all the content but I can not write and erase, it says I don’t have permission.
Any ideas?

You will probably need to authenticate as the OSMC user.

I did it with the generic password and user OSMC/OSMC.
I connected by ftp and I saw the permissions on the disk are on read only but I can not change them in the ftp (550 SITE CHMOD command failed)

How is the disk formatted?

If it’s HFS+ you will need to umount and fsck. This is the filesystem I really don’t recommend for use on OSMC. It causes us enough grief on AppleTV.