I am running a Django application on my laptop at port 8000. The app works locally and I want to make it accessible to others over the internet via SSH remote port forwarding to a VPS.
I’ve connected to my VPS using the following command:

ssh -R 9090:localhost:8000 remote_user@remote_host

I tried to confirm that the port forwarding works:

netstat -tunl | grep 9090
tcp        0      0 0.0.0.0:9090            0.0.0.0:*               LISTEN
tcp6       0      0 :::9090                 :::*                    LISTEN

I can use telnet on the VPS to connect to port 9090 and issue a GET request to retrieve the home page. This part works as expected. However, when I try to open the application in a browser using http://remote_host:9090, it does not load and I get a 503 error.
I have already added a rule to the INPUT chain of iptables on my VPS to allow incoming connections to port 9090:

sudo iptables -A INPUT -p tcp --dport 9090 -j ACCEPT

I’ve temporarily uninstalled iptables on my laptop.

My questions are:

1. Am I missing something in my setup that prevents the application from being accessible over the internet?
2. Was I wrong to assume that this method would make my app accessible over the internet without actually deploying it?