Nodejs app under nginx and same domain

I'm trying to serve two nodejs apps under the same domain, I configure nginx like this

server {   
    listen 80;     

    location /client {
        proxy_pass         http://127.0.0.1:3000;
        proxy_redirect     off;
        proxy_set_header   Host             $host;
        proxy_set_header   X-Real-IP        $remote_addr;
        proxy_set_header   X-Forwarded-For  $proxy_add_x_forwarded_for;
    }

    location / {
        proxy_pass         http://127.0.0.1:3001;
        proxy_redirect     off;
        proxy_set_header   Host             $host;
        proxy_set_header   X-Real-IP        $remote_addr;
        proxy_set_header   X-Forwarded-For  $proxy_add_x_forwarded_for;
    }

}

I can connect to the second app, the one on port 3001, but i cant connect to the one on port 3000 (App1), I get 502 Bad Gateway.

App1 is running on express 4.x, is there something else i have to configure?

server {
listen 80;
root /var/www;
server_name your-domain.com;

location /app1 {
    proxy_pass http://localhost:{YOUR_PORT};
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection 'upgrade';
    proxy_set_header Host $host;
    proxy_cache_bypass $http_upgrade;
}

location /app2 {
    proxy_pass http://localhost:{YOUR_PORT};
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection 'upgrade';
    proxy_set_header Host $host;
    proxy_cache_bypass $http_upgrade;
}
}

Try the config similar to above