When running vagrant on network that was connected to VPN, I was seeing that vagrant provisioning of docker containers had problems with pulling some of the updates for vagrant box because it wasn’t able to identify how to get to archive.ubuntu.com with an error
Failed to fetch http://us.archive.ubuntu.com/
This is what helped me and you can try to add this line to the Vagrantfile somewhere before you do docker provisioning:
config.vm.provision :shell, :inline => "echo 'nameserver 22.214.171.124' | sudo tee /etc/resolv.conf &> /dev/null", :privileged => true
This way, vagrant will attempt to use external DNS service, which in my case is 126.96.36.199.