Can you please provide more information about the issue you are experiencing? What Roku model device are you using? How are you powering the device? Is the device plugged into the TV USB port or is plugged into a wall outlet with the provided cable and adapter?
Can you also provide an ID tracker the next time this issue occurs? You can retrieve an ID tracker by pressing the Home button 5 times, followed by the Back button 5 times. Please provide this information along with your Roku serial number of your device.
With more information we will be able to assist you further.