Holding down the center button and pressing the play button for five seconds rebooted the unit and fixed the problem after I had tried everything else (powering down the router, unplugging the Firestick) I was almost ready to buy another Firestick. When I bought the one that had this problem, I had also bought another one and it had failed a few months ago. So I'm glad I found this solution. Thanks!
Non of this worked for me, but I found a different solution to my problem. Hope it helps someone else out. I was using a USB 3.0 stick in the back of the TV and apparently this was interfering with the WiFi signal. I found out because I had the same problem on my laptop: I plugged in 2 USB 3.0 external drives and the signal from them blocked the WiFi signal on my laptop. Something to do with insufficient shielding of the cables/ports etc. I used extension cables for the USB on the TV and everything works fine.
If you are still experiencing the error "Home Currently Unavailable" on your Fire TV device, please try these following steps to resolve your issue -
1. Unplug the Fire TV Stick from power, wait 10 seconds, and then plug it back in. 2. Unplug the Fire TV Stick from the TV and then plug it back in. 3. If you are using the HDMI extender, plug the Fire TV Stick directly into the TV.
4. Restart Internet Modem/Router
If these steps do not resolve the issue, please let us know.