If this is the Express model that doesn't come with a power adapter make sure the one you're using is adequate. Some TV USB ports can't supply enough power as well as some power adapters from phones, tablets, etc. Make sure the one you're using can supply at least 1 Amp. Look at the small print for something like, Output: 5V 1A.
If it did come with a power adapter and you're using it then you may just want to return it.
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