Meanwhile the problem is not solved. Devices disappear after some minutes after changing ports or restarting device.

@David-TP Same problem for me. Deco App is not showing any LAN device After plugin ethernet port on and out or restarting for few minutes all is fine, then devices disappear again. Also some devices...

Okay. Switched the ports on main Deco and now it works.

P.S.: I have no acces to my Network Attached Storage at all.

I am running a DSL-Router-Modem. Behind that I placed TP Link Deco X20 in Router Mode. DSL-Router and Deco each have its own subnet and all is running fine. Problem is, that I can not see LAN devices...

@David-TP What happens is, that when network quality is in bad state is that internet connection speed drops from 250 MBit to 30-60 MBit with high latency > 100ms instead of < 20ms. Then I can't...