Power Outages Alien Not Reconnecting to Modem


  • Start with the Hardware: Two Aliens since around last November 2019. I am on Cox Cable and purchased my own compatible Modem. I upgraded to Cox Gigablast around April of 2020 and purchased the Arris SB8200. Around May I had the first problem where on a power outage the Alien would not reconnect to the Modem. I spent about two hours on the phone with Cox over two calls and it was determined by Cox that the Modem was fine so nothing they could do. Ultimately too reconnect I had to reset Alien, start from scratch and set it up as a new system. Wife working from home and network has to be running. So Tuesday the tropical storm rolls through and naturally I am in a hard hit area of CT, 76% power outage in town but the cable remained connected. So on Generator I hooked everything up to a live outlet and it worked fine. Power came back last night so switching over from generator to power caused a reconnection of the equipment. Again the Alien would not reconnect to the modem. I unplugged everything, started with the modem first when that was running I turned on the Alien. When that was up I plugged the network cable into the modem and no WiFi. Did this more than a dozen times and could not get WiFi up and going. I was able to run a speed test twice on the Alien so it was seeing the modem as the numbers seemed accurate, but it would not setup WiFi. Ultimately I had to disconnect both Aliens and presently went back to Eero Pro. Wife's building in town still has no power so back working from home so working internet a "must".

    1. Still believe the problem is not Cox. Could the modem be the problem, Arris SB8200? The odd thing is most times I cannot run a Speed test so last night was odd that I could. Willing to buy a new modem just have to wait for a few days
    2. Did one of the updates from Alien go bad for me? It seems to me that on brief power outages everything should automatically reconnect. Which it often does. Yesterday when I went on Generator and the modem was lit up properly all I had to do was power off the Alien and power back on. Reconnected fine. Second time nothing would work.

    As I have $800.00 worth of equipment sitting here, just looking from some steps to try when I am able to reconnect in a day or two?


  • @James-Kelly said in Power Outages Alien Not Reconnecting to Modem:

    Could the modem be the problem, Arris SB8200

    To my knowledge, the SB8200 can only have one of the two WAN ports active at a time, unless your ISP provides you with two public IP's. Is the Alien the only device plugged into your modem?

    Yesterday when I went on Generator and the modem was lit up properly all I had to do was power off the Alien and power back on. Reconnected fine

    AmpliFi has a unique boot order, and in some environments if its not followed it can result in a no IP error. In a power outage, Both the modem and Alien would boot at the same time, where the Alien is recommended to be powered on first.

    What you described however is that the network was working, but simply WiFi was not. This could be a radio failure, possibly caused by the power surge.

    The steps I would try in this situation before resulting in an RMA claim would be to factory reset the Alien router, and ensure it is the only device plugged into your SB8200. Before using the app to setup the network, view the available WiFi networks and see if the Alien is broadcasting the setup SSID. If it is, then the antennas appear to be working. Setup with the mobile app and then you can enable each radio to verify all are broadcasting. To do this, follow the Additional SSID steps found in this article.


  • Outages due to the storm through here made it impossible to do anything with this before yesterday Aug 10. To clarify a couple of points, 1. The only thing (ever) plugged in the SB8200 is the router.
    2. Numerous things I cannot control are the hot summer in the US, brief power outages (2 - 5 seconds) and rolling brownouts.
    3. Also my electronics, computer, modem, router and a switch are plugged into a Cyberpower 8 Plug UPS. 4 plugs are battery backup and 4 are Surge only. When I reconnected yesterday I put the Modem and Alien router on UPS (they were on Surge before). So for long term outage this will give me ample time before the whole house generator kicks in which takes 2 - 3 minutes.

    Yesterday I took the Alien unit that was the mesh point, reset to factory defaults, and connected it to the router. Connected without a problem. Made the other unit (which was connected before to Modem) and made it the Mesh point. So all is running again.

    But my problem before was getting it to recognize the modem or to see the internet. Will have to run some test coming up by killing the power and letting it reconnect on its own. See what happens. I do not think that I should have to manually Reset to Factory Defaults every time there is a power blip. It should reconnect on its own. Unfortunately I do need a third unit as due to placement of the units one side of my house has no coverage on the porch (not practical to move things around and wife factor to consider). But have to make sure this problem does not happen again.


  • @James-Kelly said in Power Outages Alien Not Reconnecting to Modem:

    Made the other unit (which was connected before to Modem) and made it the Mesh point. So all is running again.

    Is this unit wirelessly connected or connected via ethernet? I have seen reports before where a power surge blew the WAN port on devices (Modems and routers). In this case, you have identified that the modem is fully operational so it is possible that the WAN port on this Alien is not longer working. You can test this by turning on ethernet backhaul and see if it will connect.

    FWIW, I use the Alien router (no mesh point) with the SB8200 on Xfinity with only the router plugged into the modem and when we face dips in power and my system restarts it boots up normal every time. I just face a brief 3-5 minute outage of service while the modem reboots.


  • @UI-AmpliFi
    It is all wireless no Ethernet backhaul. I use the ports on Alien for devices. I have two things that do not work on switches. And that is my problem is no reconnecting between modem and Alien router. Had to do complete resets to get it working. Last storm hammered us in Connecticut. Have 2 fifty foot plus trees down still have to cut up. So just do not have time to simulate an outage now to see what happens. Hopefully in a week or so I can try.


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