XDebug on port 9000 with a virtual machine - EADDRINUSE :::90000

I am running my Symfony application on a VirtualBox VM. PHP is running with XDebug, and it is properly configured. I know this because other people have managed to make it work with a snapshot of the same VM.

When I try to configure in VS Code XDebug, I use the following launch.json

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Listen for XDebug",
            "type": "php",
            "request": "launch",
            "port": 9000
        },
        {
            "name": "Launch currently open script",
            "type": "php",
            "request": "launch",
            "program": "${file}",
            "cwd": "${fileDirname}",
            "port": 9000
        }
    ]
}

But when I click on "Start Debugging: Listen for XDebug", I get the following error:

ERROR: listen EADDRINUSE :::9000

I tried killing the process that is using that port... and for my surprise that was the virtual machine I was trying to connect to.

What did I miss in this configuration?

from XDebug on port 9000 with a virtual machine - EADDRINUSE :::90000