@WiCreekPaddler You should enable Fast Roaming back, it is responsible for telling mobile device to move between WiFi mesh nodes. This is unlikely to fix the issue you have, but disabling it degrades...

@trogvar Start with the following TP-Link document, which discusses Ethernet backhaul: General questions about Ethernet Backhaul feature on your Deco

@koswo Deco P9 is capable of using powerline, but when it can't - troubleshooting becomes a challenge. There is no user exposure to inner workings of powerline connection of P9. You said you added...

@Xenomes Would you please share network diagram, specifically how your Deco M4 devices connect to each other and/or to router, also what is connected to the second Ethernet port of Main Deco.

@UkDavid When you have ISP router you need to keep, running Deco mesh in AP mode is the right answer. First of all, if you ever have issues with Internet link, it is much easier to convince ISP Tech...

@Eirik Open "Update Deco" in Deco app, it'll show you current firmware version of your Deco units. It'll also show if different Deco units have different firmware versions. If you updated firmware...