VirtualBox/Vagrant Error on 'vagrant up' command

I am trying to set up my Laravel Ubuntu Developement environment with Homestead but I keep getting this error when I enter the 'vagrant up' command in the vagrant CLI. It's fine up to the point of "default: Booting VM":

machine@User:~/Homestead$ vagrant up
Bringing machine 'default' up with 'virtualbox' provider...
==> default: Checking if box 'laravel/homestead' is up to date...
==> default: Clearing any previously set forwarded ports...
==> 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: 80 (guest) => 8000 (host) (adapter 1)
    default: 443 (guest) => 44300 (host) (adapter 1)
    default: 3306 (guest) => 33060 (host) (adapter 1)
    default: 5432 (guest) => 54320 (host) (adapter 1)
    default: 22 (guest) => 2222 (host) (adapter 1)
==> default: Running 'pre-boot' VM customizations...
==> default: Booting VM...
There was an error while executing `VBoxManage`, a CLI used by Vagrant
for controlling VirtualBox. The command and stderr is shown below.

Command: ["startvm", "b7d57380-a06d-4474-ad3a-edfebc787b87", "--type", "headless"]

Stderr: VBoxManage: error: The virtual machine 'homestead-7' has terminated unexpectedly during startup with exit code 1 (0x1)
VBoxManage: error: Details: code NS_ERROR_FAILURE (0x80004005), component MachineWrap, interface IMachine

• OS:================>Ubuntu 16.04.1 LTS (Xenial Xerus)

• vagrant version:===>Installed Version: 1.8.5/Latest Version: 1.8.5

• VirtualBox version:>5.1.4

• laravel/homestead:=>0.5.0

• Secure Boot:=======>OFF

via Chebli Mohamed