Help in configuration with Nginx (and Owncloud)

[pihomeserver]

Hello,

I installed Owncloud on a VPS with Nginx and php-fpm
Now i would like to link my Hubic account inside Owncloud using the openstack interface that's why i would like to use the gateway.
Unfortunaltly i don't know how to use/configure it. Owncloud is installed at the root of one of my subdomain. The gateway (simple.php) is in a subfolder called hubic. Another subfolder called cache has been created with config.php at the root path.

When i try to access the register part i got a 404 error code

Here is my nginx configuration (with a dedicated block for /hubic)

server {
    listen 80;
    listen [::]:80;
    server_name cloud.mysubdomain.fr;
    return 301 https://$server_name$request_uri;
}

server {
        server_name cloud.mysubdomain.fr;

        listen 443 ssl;
        listen [::]:443 ssl;
        include snippets/ssl-cloud.mysubdomain.fr.conf;
        include snippets/ssl-params.conf;

        index index.php;
        root /var/www/cloud;

        # set max upload size
        client_max_body_size 10G;
        fastcgi_buffers 64 4K;

        # Disable gzip to avoid the removal of the ETag header
        gzip off;

    rewrite ^/caldav((/|$).*)$ /remote.php/caldav$1 last;
    rewrite ^/carddav((/|$).*)$ /remote.php/carddav$1 last;
    rewrite ^/webdav((/|$).*)$ /remote.php/webdav$1 last;

    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 unix:/var/run/php5-fpm.sock;
        }

        location /hubic {
                index simple.php;
                rewrite ^/(.*)$ /simple.php?/$1 last;
                root /var/www/cloud/hubic;
                try_files $uri $uri/ /simple.php?$args;
        }

        # Adding the cache control header for js and css files
        # Make sure it is BELOW the location ~ \.php(?:$|/) { block
        location ~* \.(?:css|js)$ {
                add_header Cache-Control "public, max-age=7200";
                # Add headers to serve security related headers
                add_header Strict-Transport-Security "max-age=15768000; includeSubDomains; preload;";
                add_header X-Content-Type-Options nosniff;
                add_header X-Frame-Options "SAMEORIGIN";
                add_header X-XSS-Protection "1; mode=block";
                add_header X-Robots-Tag none;
                # Optional: Don't log access to assets
                access_log off;
        }    

        # 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;
        }
}

Any help is welcome.
Thank you