vagrant up でエラーが出たので、画面手順にそって操作してみた。
Bringing machine 'default' up with 'virtualbox' provider... ==> default: Checking if box 'centos/7' is up to date... ==> default: A newer version of the box 'centos/7' is available! You currently ==> default: have version '1603.01'. The latest is version '1606.01'. Run ==> default: `vagrant box update` to update. ==> default: Running provisioner: shell...
The guest machine entered an invalid state while waiting for it to boot. Valid states are 'starting, running'. The machine is in the 'paused' state. Please verify everything is configured properly and try again. If the provider you're using has a GUI that comes with it, it is often helpful to open that and watch the machine, since the GUI often has more helpful error messages than Vagrant can retrieve. For example, if you're using VirtualBox, run `vagrant up` while the VirtualBox GUI is open. The primary issue for this error is that the provider you're using is not properly configured. This is very rarely a Vagrant issue.
vagrant box update
SSH authentication failed! This is typically caused by the public/private keypair for the SSH user not being properly set on the guest VM. Please verify that the guest VM is setup with the proper public key, and that the private key path for Vagrant is setup properly as well.