@LostPlot I have Synology NAS with overnight shutdown/startup schedule, that does not impact my Deco mesh. Hopefully it were just that cable between Main Deco and switch. If the issue were with...

@LostPlot Usually, when switch does not support Deco mesh Ethernet backhaul protocol, both Satellites will use WiFi backhaul. In your case, Summerhouse Deco can still talk to Bedroom Deco over...

@LostPlot Thank you. So, this is what happens in this test: 1. Both Satellites originally use Ethernet backhaul and report as connected to Main Deco. 2. You unplug Ethernet cable between Main Deco...

@LostPlot This is your network diagram, I believe: I would like to suggest the following test: 1. Unplug Ethernet cable connecting Main Deco to the switch, from Main Deco and from the switch. 2. See...

@Rapo2 Check the following TP-Link KB article: https://community.tp-link.com/en/home/forum/topic/624082

@rodrigue741 That usually means Deco unable to negotiate gigabit speed on Ethernet link. That usually points at issues with cabling. There are multiple ways to test that theory, for example: 1. Swap...