Firestick rebooting

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Hey goodie…

Here ya go

1. Overheating (get it away from TV)
2. Power (plug into wall outlet)
3. Storage full

Firestick 4K keeps rebooting

Two of my Firestick 4Ks keep rebooting on their own when we are watching TV on our Firestick. I have checked for updates and they are up to date. How do I fix this problem? Thanks!