@TP-Link_Deco So to document things a bit further, I set up port mirroring on the Deco M9 wired connection. Mirroring was forwarded to my laptop that is connected by wire to the same switch. The PC...

@TP-Link_Deco Hi, thanks for your response. Normally I have 2 Deco's with wired backhaul. Now for debugging reasons I disconnected the auxilliary Deco and configured the remaining one as main unit....

For around 6 months, I had the following setup working flawlessly: Modem/Router->managed switch->DecoM9+wired clients The modem/router is provided by my ISP and DHCP cannot be disabled unfortunately,...