Double port forwarding kubernetes + docker

Summary:

I have a docker container which is running kubectl port-forward, forwarding the port (5432) of a postgres service running as a k8s service to a local port (2223).
In the Dockerfile, I have exposed the relevant port 2223. Then I ran the container by publishing the said port (-p 2223:2223)

Now when I am trying to access the postgres through psql -h localhost -p 2223, I am getting the following error:

psql: server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.

However, when I do docker exec -ti to the said container and run the above psql command, I am able to connect to postgres.

Dockerfile CMD:

EXPOSE 2223
CMD ("bash", "-c", "kubectl -n namespace_test port-forward service/postgres-11-2 2223:5432")

Docker Run command:

docker run -it --name=k8s-conn-12 -p 2223:2223 my_image_name:latest

Output of the docker run command:

Forwarding from 127.0.0.1:2223 -> 5432

So the port forwarding is successful, and I am able to connect to the postgres instance from inside the docker container. What I am not able to do is to connect from outside the container with the exposed and published port