Have you verified that it's not the TV? Does it work with other devices?
With these Roku devices that are powered via a USB cable it's often the power source that's the culprit. If you're using the TV's USB port to power the stick, try using a USB power adapter/charger from a phone or tablet. Look for one that can provide at least 1 Amp. The fine print should say something like, Output: 5V 1A (or 1000mA). Anything over 1A is good, less is not.
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