Why does Jenkins give ‘permission denied’ error when using Ubuntu, but not when bash-ing into DIND image?

Jenkins and docker

Hello, I have installed jenkins on my main computer using docker desktop with the recommended current jenkins image. On that same windows computer I created an ubuntu VM with vmware. On the ubuntu VM I installed the docker engine. I also installed sysbox-runc runtime to use with dind. In jenkins I added the ubuntu vm has a permanent agent and everything is working except the docker client commands.

My JenkinsFile look like this

pipeline {
agent { docker {
    image 'costum dind image with java and maven'
    registryCredentialsId 'credential'
    args '-v /var/run/docker.sock:/var/run/docker.sock'
 } }
stages {
    codecheckout
    ...
    stage('compile') {
        steps {
            sh 'mvn compile'
        }
    }

    stage('test') {
        steps {
            sh 'mvn test'
        }
    }

    stage('build jar') {
        steps {
            sh 'mvn clean compile assembly:single'
        }
    }

    stage('docker build') {
        steps {
            sh 'docker build -t img/img .'
        }
    }
}

}

It all work except the last one sh ‘docker build -t img/img .’
It says ERROR: permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get "http://%2Fvar%2Frun%2Fdocker.sock/_ping": dial unix /var/run/docker.sock: connect: permission denied

My jenkins start the agent on ubuntu via the launch method "Launch agents via SSH".

I added the ssh user that jenkins is using to start the agent in the docker group. It still does the error. So far the only way it work is if I cheat and put 777 perm on docker.sock.

The wierd thing is when using the ubuntu terminal, I run a dind image and go on it, I don’t have any error and all docker commands work. It is only when jenkins does it with the docker agent that it has some kind of permission issues.

I’ve spend more so much time on this, does someone have ideas?