Mopidy, Raspberry Pi & Usb Drive access issue

Hello to everyone,

Let me inform you that I am a newbie user to Linux systems. I just managed to install the wonderful mopidy application on my Raspbery pi 2 B device but I have a problem while i am trying to play music from my external usb hard drive (I use an external disk as a private NAS cloud).

I modify the configuration file as follows:

[core]
cache_dir = /var/cache/mopidy
config_dir = /etc/mopidy
data_dir = /var/lib/mopidy

[logging]
config_file = /etc/mopidy/logging.conf
debug_file = /var/log/mopidy/mopidy-debug.log

[local]
media_dir = /media/Disks_Drives/Skari/Music

[m3u]
playlists_dir = /media/Disks_Drives/Skari/Music/playlists

and here is the status report with the OSError:

Dec 27 00:23:14 syn-server.com mopidy[10679]:     compat.reraise(*self._data['exc_info'])
Dec 27 00:23:14 syn-server.com mopidy[10679]:   File "/usr/lib/python2.7/dist-packages/pykka/compat.py", line 12, in reraise
Dec 27 00:23:14 syn-server.com mopidy[10679]:     exec('raise tp, value, tb')
Dec 27 00:23:14 syn-server.com mopidy[10679]:   File "/usr/lib/python2.7/dist-packages/pykka/actor.py", line 201, in _actor_loop
Dec 27 00:23:14 syn-server.com mopidy[10679]:     response = self._handle_receive(message)
Dec 27 00:23:14 syn-server.com mopidy[10679]:   File "/usr/lib/python2.7/dist-packages/pykka/actor.py", line 295, in _handle_receive
Dec 27 00:23:14 syn-server.com mopidy[10679]:     return callee(*message['args'], **message['kwargs'])
Dec 27 00:23:14 syn-server.com mopidy[10679]:   File "/usr/lib/python2.7/dist-packages/mopidy/m3u/playlists.py", line 69, in as_list
Dec 27 00:23:14 syn-server.com mopidy[10679]:     for entry in os.listdir(self._playlists_dir):
Dec 27 00:23:14 syn-server.com mopidy[10679]: OSError: [Errno 13] Permission denied: '/media/Disks_Drives/Skari/\xce\x9c\xce\xbf\xcf\x85\xcf\x83\xce\xb9\xce\xb

as a result the web GUI or the mobile client does not display the content in the “Music” folder of my drive. How can i to solve this permission access issue here?

Thank you in advance!