Debian 8 - Issue with Mattermost service

Hello,

I'm quite new to mattermost. I've been trying to install it on a Debian 8.

Everything is going well, my nginx is well configured as well as my mattermost installation.

I've been experiencing issue when I'm trying to run the mattermost daemon (/etc/init.d/mattermost). The service status says it's active and working:
● mattermost.service - LSB: Mattermost Group Chat
Loaded: loaded (/etc/init.d/mattermost)
Active: active (exited) since Mon 2016-02-01 13:46:21 CET; 8min ago
Process: 3503 ExecStop=/etc/init.d/mattermost stop (code=exited, status=0/SUCCESS)
Process: 3508 ExecStart=/etc/init.d/mattermost start (code=exited, status=0/SUCCESS)

Feb 01 13:46:21 vps242230.ovh.net mattermost[3508]: Starting Mattermost: mattermost.

However, the website does not work. It only works when I run manually /opt/mattermost/bin/platform.
I see the request going trough nginx, but they do not seem to be forwarded to the mattermost daemon (I have a 502 error Bad gateway occuring).

Does anybody is experiencing the same issue ?

here is my service declaration from the documentation:

#! /bin/sh
### BEGIN INIT INFO
# Provides:          mattermost
# Required-Start:    $network $syslog
# Required-Stop:     $network $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Mattermost Group Chat
# Description:       Mattermost: An open-source Slack
### END INIT INFO
PATH=/sbin:/usr/sbin:/bin:/usr/bin
DESC="Mattermost"
NAME=mattermost
MATTERMOST_ROOT=/opt/mattermost
MATTERMOST_GROUP=mattermost
MATTERMOST_USER=mattermost
DAEMON="$MATTERMOST_ROOT/bin/platform"
PIDFILE=/var/run/$NAME.pid
SCRIPTNAME=/etc/init.d/$NAME

. /lib/lsb/init-functions

do_start() {
    # Return
    #   0 if daemon has been started
    #   1 if daemon was already running
    #   2 if daemon could not be started
    start-stop-daemon --start --quiet \
        --chuid $MATTERMOST_USER:$MATTERMOST_GROUP --chdir $MATTERMOST_ROOT --background \
        --pidfile $PIDFILE --exec $DAEMON --test > /dev/null \
        || return 1
    start-stop-daemon --start --quiet \
        --chuid $MATTERMOST_USER:$MATTERMOST_GROUP --chdir $MATTERMOST_ROOT --background \
        --make-pidfile --pidfile $PIDFILE --exec $DAEMON \
        || return 2
}

#
# Function that stops the daemon/service
#
do_stop() {
    # Return
    #   0 if daemon has been stopped
    #   1 if daemon was already stopped
    #   2 if daemon could not be stopped
    #   other if a failure occurred
    start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 \
        --pidfile $PIDFILE --exec $DAEMON
    RETVAL="$?"
    [ "$RETVAL" = 2 ] && return 2
    # Wait for children to finish too if this is a daemon that forks
    # and if the daemon is only ever run from this initscript.
    # If the above conditions are not satisfied then add some other code
    # that waits for the process to drop all resources that could be
    # needed by services started subsequently.  A last resort is to
    # sleep for some time.
    start-stop-daemon --stop --quiet --oknodo --retry=0/30/KILL/5 \
        --exec $DAEMON
    [ "$?" = 2 ] && return 2
    # Many daemons don't delete their pidfiles when they exit.
    rm -f $PIDFILE
    return "$RETVAL"
}

case "$1" in
start)
        [ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC" "$NAME"
        do_start
        case "$?" in
                0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
                2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
        esac
        ;;
stop)
        [ "$VERBOSE" != no ] && log_daemon_msg "Stopping $DESC" "$NAME"
        do_stop
        case "$?" in
                0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
                2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
        esac
        ;;
status)
    status_of_proc "$DAEMON" "$NAME" && exit 0 || exit $?
    ;;
restart|force-reload)
        #
        # If the "reload" option is implemented then remove the
        # 'force-reload' alias
        #
        log_daemon_msg "Restarting $DESC" "$NAME"
        do_stop
        case "$?" in
        0|1)
                do_start
                case "$?" in
                        0) log_end_msg 0 ;;
                        1) log_end_msg 1 ;; # Old process is still running
                        *) log_end_msg 1 ;; # Failed to start
                esac
                ;;
        *)
                # Failed to stop
                log_end_msg 1
                ;;
        esac
        ;;
*)
        echo "Usage: $SCRIPTNAME {start|stop|status|restart|force-reload}" >&2
        exit 3
        ;;
esac

exit 0

Keep up the good work
Regards,
Samir Boulil