Impossible de démarrer le service PlexMediaserver

Mon plexmediaserver.service ressemble à ce qui suit.

    [Unit]
    Description=Plex Media Server for Linux
    After=network.target

    [Service]
    Environment="PLEX_MEDIA_SERVER_APPLICATION_SUPPORT_DIR=/var/lib/plexmediaserver/        Library/Application Support"
    Environment=PLEX_MEDIA_SERVER_HOME=/usr/lib/plexmediaserver
    Environment=PLEX_MEDIA_SERVER_MAX_PLUGIN_PROCS=6
    Environment=PLEX_MEDIA_SERVER_TMPDIR=/tmp
    Environment=LD_LIBRARY_PATH=/usr/lib/plexmediaserver
    ExecStartPre=/bin/sh -c '/usr/bin/test -d "${PLEX_MEDIA_SERVER_APPLICATION_SUPPORT_DIR}" || /bin/mkdir -p "${PLEX_MEDIA_SERVER_APPLICATION_SUPPORT_DIR}"'
    ExecStart=/bin/sh -c '/usr/lib/plexmediaserver/Plex\ Media\ Server'
    Type=simple
    User=plex
    Group=plex
    Restart=on-failure
    RestartSec=5
    StartLimitInterval=60s
    StartLimitBurst=3

    [Install]
    WantedBy=multi-user.target

L'erreur que j'obtiens est la suivante

     plexmediaserver.service - Plex Media Server for Linux
       Loaded: loaded (/etc/systemd/system/plexmediaserver.service; enabled; vendor preset: enabled)
       Active: inactive (dead) (Result: exit-code) since Sun 2016-12-11 17:15:21 EST; 6min ago
      Process: 4417 ExecStartPre=/bin/sh -c /usr/bin/test -d "${PLEX_MEDIA_SERVER_APPLICATION_SUPPORT_DIR}" || /bin/mkdir -p "${PLEX_MEDIA_SERVER_APPLICATION_SUPPORT_DIR}" (code=exited, status=217/USER)
     Main PID: 3588 (code=killed, signal=TERM)

    Dec 11 17:15:21 ubuntuServer systemd[1]: plexmediaserver.service: Service hold-off time over, scheduling restart.
    Dec 11 17:15:21 ubuntuServer systemd[1]: Stopped Plex Media Server for Linux.
    Dec 11 17:15:21 ubuntuServer systemd[1]: plexmediaserver.service: Start request repeated too quickly.
    Dec 11 17:15:21 ubuntuServer systemd[1]: Failed to start Plex Media Server for Linux.