@GaborN On any device connected to Deco mesh, open web site www.whatismyip.com and it will tell you how Internet sees your location. Change Deco mesh to Access Point mode, and the problem should go...

@Sivin It is possible something is wrong with Ethernet cables. It is also possible your ISP Router does not support Deco Ethernet backhaul. Very rare case, but happens. Also, if your ISP Router...

@PK1212 It is impossible. You should return that Deco unit to seller for refund.

@Synfalle This will not work, because Deco X50-PoE does not support EasyMesh. See TP-Link Deco Mesh vs EasyMesh vs OneMesh vs Omada Mesh What's the Difference?

@Davecuthbert Try adding X10 with blinking blue light manually to your Deco mesh: How to add an additional unit to your Deco network

@N1XKP Take Deco E4 units back to the house, place near Main Deco and let them connect to Main Deco over WiFi (do not wire them). If they do connect over WiFi, in Deco app check for each Satellite E4...