nginx - 502 bad gateway - php

Question

First of all let me tell you that I am not an expert on web-servers and things like that.
I'm trying to set-up a cloud system on raspi following this link:
RasPi Owncloud
However, when I try to connect at my IP I get a fantastic 502 Bad Gateway. I googoled (a lot) and all solution given they didn't work for me :(
Also, I checked apache, nginx and php5 logs and they don't show error whatsoever.
Can you please help me to narrow down the problem?
cat /etc/nginx/nginx.conf
user www-data;
worker_processes 4;
pid /run/nginx.pid;
events {
worker_connections 768;
# multi_accept on;
}
http {
##
# Basic Settings
##
sendfile on;
tcp_nopush on;
tcp_nodelay on;
keepalive_timeout 65;
types_hash_max_size 2048;
# server_tokens off;
# server_names_hash_bucket_size 64;
# server_name_in_redirect off;
include /etc/nginx/mime.types;
default_type application/octet-stream;
##
# SSL Settings
##
ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
ssl_prefer_server_ciphers on;
##
# Logging Settings
##
access_log /var/log/nginx/access.log;
error_log /var/log/nginx/error.log;
##
# Gzip Settings
##
gzip on;
gzip_disable "msie6";
# gzip_vary on;
# gzip_proxied any;
# gzip_comp_level 6;
# gzip_buffers 16 8k;
# gzip_http_version 1.1;
# gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;
##
# Virtual Host Configs
##
include /etc/nginx/conf.d/*.conf;
include /etc/nginx/sites-enabled/*;
}
#mail {
# # See sample authentication script at:
# # http://wiki.nginx.org/ImapAuthenticateWithApachePhpScript
#
# # auth_http localhost/auth.php;
# # pop3_capabilities "TOP" "USER";
# # imap_capabilities "IMAP4rev1" "UIDPLUS";
#
# server {
# listen localhost:110;
# protocol pop3;
# proxy on;
# }
#
# server {
# listen localhost:143;
# protocol imap;
# proxy on;
# }
#
}
cat /etc/nginx/sites-available/default
upstream php-handler {
server 127.0.0.1:9000;
#server unix:/var/run/php5-fpm.sock;
}
#server {
# listen 80;
# server_name 172.16.0.2;
# return 301 https://$server_name$request_uri; # enforce https
#}
server {
listen 443 ssl;
server_name 172.16.0.2;
ssl_certificate /etc/nginx/cert.pem;
ssl_certificate_key /etc/nginx/cert.key;
# Path to the root of your installation
root /var/www/owncloud;
client_max_body_size 1000M; # set max upload size
fastcgi_buffers 64 4K;
rewrite ^/caldav(.*)$ /remote.php/caldav$1 redirect;
rewrite ^/carddav(.*)$ /remote.php/carddav$1 redirect;
rewrite ^/webdav(.*)$ /remote.php/webdav$1 redirect;
index index.php;
error_page 403 /core/templates/403.php;
error_page 404 /core/templates/404.php;
location = /robots.txt {
allow all;
log_not_found off;
access_log off;
}
location ~ ^/(?:\.htaccess|data|config|db_structure\.xml|README) {
deny all;
}
location / {
# The following 2 rules are only needed with webfinger
rewrite ^/.well-known/host-meta /public.php?service=host-meta last;
rewrite ^/.well-known/host-meta.json /public.php?service=host-meta-json last;
rewrite ^/.well-known/carddav /remote.php/carddav/ redirect;
rewrite ^/.well-known/caldav /remote.php/caldav/ redirect;
rewrite ^(/core/doc/[^\/]+/)$ $1/index.html;
try_files $uri $uri/ index.php;
}
location ~ \.php(?:$|/) {
fastcgi_split_path_info ^(.+\.php)(/.+)$;
include fastcgi_params;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
fastcgi_param PATH_INFO $fastcgi_path_info;
fastcgi_param HTTPS on;
fastcgi_pass php-handler;
}
# Optional: set long EXPIRES header on static assets
location ~* \.(?:jpg|jpeg|gif|bmp|ico|png|css|js|swf)$ {
expires 30d;
# Optional: Don't log access to assets
access_log off;
}
}