Elastic-beanstalk service listening to non-standard port

I am trying to deploy on AWS Elastic Beanstalk a Dockerized server (actually Minecraft/Forge server) that listens to port 25565. The configuration I’d like to use is a simple single-container docker configuration.

I tested the Docker image locally on my desktop and it works as expected (a Minecraft client can connect to it).

I can see that the AWS EB environment is started correctly (green) and the logs of my server indicate that it comes up correctly. As the environment is brought up, I see that a new security group is created for it. I go and edit it to open the 25565 TCP and UDP port, allowing connection from anywhere.

However, all connections from the internet to the allocated Elastic IP are refused no matter what I do – tested from both a minecract client and a stupid netcat command-line.

I tried to redeploy the environment with and without a proxy, with the same results.

What am I missing?

Source: StackOverflow