Unable to SSH Vagrant VM from other node

Vagrant
1

I have deployed my vagrant machine using the docker provider. I am able to access it from local.

My Vagrantfile

Vagrant.configure(2) do |config|
    ENV["LC_ALL"] = "en_US.UTF-8"

    config.vm.hostname = "dev-machine1"
    config.vm.provider "docker" do |d|
        d.image = "tknerr/baseimage-ubuntu:18.04"
        d.has_ssh = true
    end
    config.vm.network "forwarded_port", guest: 80, host: 8080, id: "nginx", auto_correct: true 
    config.ssh.insert_key = false
    config.ssh.forward_agent = true
    config.vm.provision "shell" do |s|  
        ssh_pub_key = File.readlines("/root/.ssh/vagrant1.pub").first.strip # /root/.ssh/vagrant-sample
        s.inline = <<-SHELL
            echo #{ssh_pub_key} >> /home/vagrant/.ssh/authorized_keys
            directory="/root/.ssh/"
            if [ ! -d "$directory" ]; then
                mkdir -p "$directory"
                echo "Directory '$directory' created."
            else
                echo "Directory '$directory' already exists."
            fi
            # sudo touch /root/.ssh/authorized_keys
            sudo echo #{ssh_pub_key} >> /root/.ssh/authorized_keys
        SHELL
    end            
    config.vm.provision "shell", path: ".provision/bootstrap.sh", privileged: false
end

I verified the public keys on the host machine as well as inside the container. They are correct. Able to SSH on port 2201 in local.

$ ssh -i vagrant1 vagrant@<my-other-node-where vagrant-vm-exists-ip> 
Permission denied (public key)