This is a result of attempting to access the Blade 2 via and/Vuzix View prior to authorizing the machine.
Make sure ADB Debugging is turned on. Upon receiving the prompt to allow debugging via the connected device, click OK.
If a prompt to authorize did not pop-up unplug and replug the USB.
If that did not trigger the prompt, try multiple ports and multiple cables.
If the prompt still is not present, try restarting the Blade 2 and restarting the machine.