ボックスcentos / 7を使おうとすると、MacOSMojaveとVagrantバージョン1.9.3で同じ問題が発生しました。
$ vagrant up
Bringing machine 'default' up with 'virtualbox' provider...
==> default: Box 'centos/7' could not be found. Attempting to find and install...
default: Box Provider: virtualbox
default: Box Version: >= 0
The box 'centos/7' could not be found or
could not be accessed in the remote catalog. If this is a private
box on HashiCorp's Atlas, please verify you're logged in via
`vagrant login`. Also, please double-check the name. The expanded
URL and error message are shown below:
URL: ["https://atlas.hashicorp.com/centos/7"]
Error: The requested URL returned error: 404 Not Found
Vagrant 2.2.5にアップデートしましたが、期待どおりに機能しました。
Bringing machine 'default' up with 'virtualbox' provider...
==> default: Box 'centos/7' could not be found. Attempting to find and install...
default: Box Provider: virtualbox
default: Box Version: >= 0
==> default: Loading metadata for box 'centos/7'
default: URL: https://vagrantcloud.com/centos/7
==> default: Adding box 'centos/7' (v1902.01) for provider: virtualbox
default: Downloading: https://vagrantcloud.com/centos/boxes/7/versions/1902.01/providers/virtualbox.box
default: Download redirected to host: cloud.centos.org
==> default: Successfully added box 'centos/7' (v1902.01) for 'virtualbox'!
VAGRANT_LOG=DEBUG vagrant up
して、役立つ出力を取得します。