You might recall a few months ago when the Nexus Player started knocking WiFi networks offline following an update. Now, it looks like something similar is happening with the Google Home Max. Owners of the TP-Link Archer C7 report consistent issues with network crashes when a Home Max is online—Google and TP-Link are on the case.
According to the Google Product Forums, the problem crops up as soon as a Home Max is added to a network powered by the Archer C7. It's a weirdly specific bug, but TP-Link has reportedly pointed the finger at so-called MDNS packets that keep a live connection with Cast devices. That's what Google blamed for the issues with the Nexus Player. Instead of sending these packets in 20-second intervals, the Home Max is apparently spamming thousands of them and overloading the router.
It's not clear why the TP-Link router is the only one affected, but it's possible there are others that just haven't been reported. The Archer C7 just happens to be a very popular router. If you're affected, you can help Google track down the issue by submitting feedback from the Google Home app with the keywords "GHT3 - Unable to setup Max to network."
- Google Product Forums