@DanielSweet  this is a joke 2 years later still the same issue, after 3 hours on customer support they told me my units are faulty, even though I bought 3 then added a fourth layer, after trying them all they are insisted they are faulty which is what a one I. A million chance. FIX THIS ISSUE

  @TP-Link 

I have a Deco XE75 with 2 Deco units (both XE75). I have 1 LAN port connected to the modem for internet connection while 2 more LAN port connected to 2 NAS. 1 NAS is on fixed IP while the other one have reserved IP allocated to it (set on the Deco).

This is working fine until my modem was faulty. After replacing the modem, internet is back to usual. I can access the internet using my wifi. However, the 2 LAN port connected to the NAS are not working. I have restarted the router, the NAS or even pull out and put back the cable, but LAN on Deco doesn't seems to work.

This seems to me similar to problem  [Deco] WAN/LAN auto-sensing.  How can I resolve this issue?

Thanks.

  @firemelt 

I have the same issue, using Deco M9 Plus V2. 

1st: (tv room) directly connected to Router via cable 

2nd: (kitchen) wifi connection to 1st

3rd: (office) cable connection (router - - > switch - - > deco). Deco ignores the cable and connects to the kitchen deco via wifi.

I have also tried to connect the 3rd/office deco directly (router - > deco), deco still connects wifi to kitchen. 

The cable works. If I connect it directly to computer, I get internet access immediately with 930 Mbit speed.

I also have this problem....2 x Decos in AP mode connected via ethernet.... ignores ethernet & just uses wifi. :(

  @David-TP 

Hello. I am experiencing the same problem with my Deco (X55) system as well. I have tried doing the things you have mentioned but none of that has changed anything. I have also found no issues with the cable I am using. I am using the Deco system in wifi router mode. The issue could be related to [Deco] WAN/LAN auto-sensing. We need the means to assign the ports as LAN or WAN. This doesn't seem like a difficult feature request.

Mine was working then it stopped.

I have a pc which is connected to deco mesh wifi and to a decomesh unit via ethernet cable. 

The pc automatically used the ethernet connection for days but today inoticed its using the wifi insted. I dont know why or how to get it to change back.

I have the same problem.

I have 4 Deco M4R working as Access Points since 3 years ago.

Three of them are connected to a switch using a ethernet cable and the other one is using wifi.

All was working fine with this scenario but, 2 months ago, the decos connected by cable (except the main deco) stopped working.

I've found that unplugging the ethernet cable makes them to work.

@TP-Link_Deco

I have the same problem.

Downstairs I have a switch plugged into a Deco S4. The Deco S4 is connected via wifi to the main Deco which is plugged into the router.

There is no internet via the switch. The cables are brand new and the devices work fine when I connect them direct to the wifi on the Router itself.

Regards

Sean