Try this: In your router, set up different passwords for the 5GHz and 2.4 GHz channels. Then your Fire TV will be forced to use one or the other. If one doesn't work, try the other.
Sir, I just tried this with no avail. My fire stick actually don’t recognize the 5 ghz connection, only the 2.4. Everything else is tried based on the recs on the previous posts, with no resolution, besides buying a HDMI extender. I have the same issue as everyone else. I get to watch ~30 minutes of Hulu before connection slows, then reboot and repeat. I’ve had this stick for around 5 months and only for past week this issue arose. I refuse to pay for an extender and would rather buy another device.
Amazon you clearly have an issue with your 4K fire stick - so many customers all with the same issue with dropping internet connection. Granted the suggestions you post are best practice, but clearly the the issue returns when other WiFi connected devices on the network are working without issue. If this were a misconfigured WiFi router all WiFi connected devices would exhibit the same dropped connection issue. I have an Apple TV 4K that has never dropped off the network.
please step up and own the issue and stop hiding behind the hey reboot your router or fire stick !