@Rtiamlee Yes. Consider replacing that cable.

@mousehunt >If I connect my devices to the Deco main unit, isn't the traffic speed still limited by the connection between the Deco main unit and C9 which is 1Gb? This is correct. Why would this be a...

@Rtiamlee I would say, the problem is with the Ethernet cable. Deco M5 has gigabit port. Looks like it can't negotiate gigabit and decided not to negotiate 100Mbit, switching to WiFi backhaul...

@ManojV97 Try again, some options disappear from Deco app occasionally. I lost an option to choose Main Deco, few days ago. Got it back after I restarted smartphone. Just closing and opening Deco app...

@Wobbo This is one of commonly used methods to check if device has Internet access. I am not saying it is the best one or it is the right one, just explaining what you see.

@gnino Yes, that would be useful feature, and if you check this forum it were discussed few times. Hopefully, TP-Link will implement it eventually. Till then, there are only workarounds. You've got...