Can you post the logs/output for your attempt?
It seems to work fine for me.
Bringing machine 'default' up with 'virtualbox' provider...
==> default: Importing base box 'discourse-16.04'...
==> default: Matching MAC address for NAT networking...
==> default: Setting the name of the VM: discourse_default_1467544808688_93034
==> default: Clearing any previously set network interfaces...
==> default: Preparing network interfaces based on configuration...
default: Adapter 1: nat
default: Adapter 2: hostonly
==> default: Forwarding ports...
default: 3000 => 4000 (adapter 1)
default: 1080 => 4080 (adapter 1)
default: 22 => 2222 (adapter 1)
==> default: Running 'pre-boot' VM customizations...
==> default: Booting VM...
==> default: Waiting for machine to boot. This may take a few minutes...
default: SSH address: 127.0.0.1:2222
default: SSH username: vagrant
default: SSH auth method: private key
default: Warning: Connection timeout. Retrying...
default:
default: Vagrant insecure key detected. Vagrant will automatically replace
default: this with a newly generated keypair for better security.
default:
default: Inserting generated public key within guest...
default: Removing insecure key from the guest if its present...
default: Key inserted! Disconnecting and reconnecting using new SSH key...
==> default: Machine booted and ready!
==> default: Checking for guest additions in VM...
default: The guest additions on this VM do not match the installed version of
default: VirtualBox! In most cases this is fine, but in rare cases it can
default: prevent things such as shared folders from working properly. If you see
default: shared folder errors, please make sure the guest additions within the
default: virtual machine match the version of VirtualBox you have installed on
default: your host and reload your VM.
default:
default: Guest Additions Version: 5.0.18
default: VirtualBox Version: 4.3
==> default: Configuring and enabling network interfaces...
==> default: Mounting shared folders...
default: /vagrant => /home/cpradio/Server/git/discourse