The problem

You are logged in as root on the VM web-1, so no command needs sudo. The shop backend runs as orders.service, defined in /etc/systemd/system/orders.service. nginx runs as nginx.service in front of it. An hour ago a colleague changed the port in the ExecStart= line of orders.service, and now the site answers 502.

You check the state of both services, load the edited unit file and restart the backend. A unit name without a suffix means .service: systemctl status orders and systemctl status orders.service do the same thing.