Redash and PostgreSQL in local docker (Self-hosted): Connection Test Failed: could not send SSL negotiation packet: Resource temporarily unavailable

Issue Summary

I have setup redash using this steps: https://redash.io/help/open-source/dev-guide/docker

I also have a PostgreSQL database running in another container in the docker.

So now my docker containers look like this:

I’m trying to set up a database connection to PostgreSQL that is present as a separate container in the docker.

My postgresql configuration looks like below:

Here the host “172.17.0.3” is the container IPAddress of the postgresql.

But after clicking the “Test Connection”, I’m getting “Connection Test Failed: could not send SSL negotiation packet: Resource temporarily unavailable” error as shown in the above picture.

The container detail of the postgresql in the docker is as follows:

"Gateway": "172.17.0.1"
"IPAddress": "172.17.0.3"
"Ports": {
    "5432/tcp": [
        {
            "HostIp": "0.0.0.0",
            "HostPort": "5432"
        }
    ]
}
"PortBindings": {
    "5432/tcp": [
        {
            "HostIp": "",
            "HostPort": "5432"
        }
    ]
}

So, what is causing this issue? Any help is appreciated.

Technical details: