The Roku 3 device came with a WiFi Direct remote. It has to be paired with the Roku device. If it lost connectivity, it would be unresponsive. Check to see if the device is still paired to the Roku 3.
Download the Roku app and use the remote feature there to navigate the menu, looking for the details of the remote that's connected. If no remote shows, it lost pairing somehow and should be paired again.
DBDukes Roku Community Streaming Expert Note: I am not a Roku employee.
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