Please change the permissions to 0770

Hello folks!
Little problem with a noob here...
First of all, my network architecture:
Raspberry Pi #1 ( running Raspbian Stretch with ownCloud X.
Raspberry Pi #2 ( running Openelec (Kodi) with an external USB HD attached.

I've mounted the USB HD on Pi #1 through CIFS using the following fstab:
// /MEDIA cifs guest,uid=1000,gid=1000,_netdev,x-systemd.automount 0 0

So far so good, all the files on Pi #2 external HD are shown on Pi #1 /MEDIA directory.

But... when i set the data folder to /MEDIA/ownClouddrive on OwnCloud config page, it returns an error saying “your data directory can be accessed by another device. Please change directory permissions to 0770” or something like that.
The question is, I need to access that directory by another device (i.e. my Win10 laptop), and at the same time I need to upload photos to that directory from my cellphone using OwnCloud app.
Is there any way to solve this problem?

Thank you very much and sorry for my bad english.

Hello, you must go to the mount point, assign owner and group to www-data or http user that you are using, example:

chown -R www-data: www-data mount point
The directory must have the 0750 permissions, example:
chmod 0750 directory

sorry for my bad english.