See the attached screenshots.
First, click the gear icon to get to the settings for your device, then click the button to delete the device. Then, let the device go through its reboot (red and green lights blinky blinky). You can do a paper-clip reset on the device for good measure.
Then, click "Add device", under the orange and white "OBi dashboard" column on the left side of the portal page, and your OBi back on the portal, using the **5 method.