An error occurred in the underlying SSH library that Vagrant uses. The error message is shown below. In many cases, errors from this library are caused by ssh-agent issues. Try disabling your SSH agent or removing some keys and try again. If the problem persists, please report a bug to the net-ssh project. timeout during server version negotiating
以上のようなエラーが出た場合には、Vagrantfileを以下のように書き換えることで対応可能です。
vb.customize ['modifyvm', :id, "--natdnshostresolver1", "on"] ↓ vb.customize ['modifyvm', :id, "--natdnshostresolver1", "off"]
