How can I use external hard drive via USB connection on a virtual machine using VirtualBox?

I ejected the hard disk from OS X host, then the disk becomes available in OS X virtual machine.

Clicking on the disk throws an error:

[![enter image description here](https://i.stack.imgur.com/bm7J7.jpg)](https://i.stack.imgur.com/bm7J7.jpg)

USB Settings:

[![enter image description here](https://i.stack.imgur.com/TdDif.jpg)](https://i.stack.imgur.com/TdDif.jpg)

Why is that?

EDIT: I added external drive to the USB panel. I am still getting an error `Failed to attach the USB device Seagate Expansion to the virtual machine El Capitan3.

```
Failed to create a proxy device for the USB device. (Error: VERR_PDM_NO_USB_PORTS).

Result Code: NS_ERROR_FAILURE (0x80004005)
Component: ConsoleWrap
Interface: IConsole {872da645-4a9b-1727-bee2-5585105b9eed}

```

[![enter image description here](https://i.stack.imgur.com/xJSrO.png)](https://i.stack.imgur.com/xJSrO.png)