@DanielSweet 
Same issue wifi working but Lan wire says good bye in occasions 

@TP-Link_Deco you need to research more on this and come with conclusive resolution it is widespread issue and reported in many forums 

@DanielSweet I have exactly the same issue

@tplink 

I am having a similar issue.

I have TP-link deco E4 - AC1200 whole home mesh wi-fi system (2-pack)

I have them set up and they work well wirelessly. I recently ran an ethernet cable from my lounge (main Deco Unit) to the Deco unit in my bedroom to try create an ethernet backhaul, as soon as I plug it in my blue TP link light on the top of the unit goes red and I lose internet on all units.

I have tried through a switch and directly to the main deco and i have the same issue every time.

I have followed the config below with no success. 

Please help

@TP-Link hi I have the same issue my Linux is connected to my M5 via ethernet and even though its connected to the Internet but I cannot access it via another device I.e. I cannot ssh into it.

When I reboot the deco m5 which my Linux is connected to I would be able to gain access fine but then after a few hours it would be unaccessible again.

Can you please help? It's really annoying!

@TP-Link 

TP-Link wrote

@Samsilv @BabyPanda 

Hi, sorry for the delay.

Since many users echoed with the same issue but did not provide enough details, it was quite hard to finally locate the problem;

If possible, could you please refer to the following suggestions:

1. What are the model number as well as the firmware version? Was it also Deco M5 with firmware 5.3?
2. Can I have a picture of the network topology, such as:
3. When the Ethernet connection failed to get internet service, what was the IP address on these devices?--how to check the IP settings (https://www.tp-link.com/support/faq/841/)--a picture of it would be highly appreciated;
4. In case it was the cable& port issue, please try to switch the port and change a new cable;

 After that, you could leave me a private message for notice;

Thank you very much.

TP-Link wrote

@Samsilv @BabyPanda 

Hi, sorry for the delay.

Since many users echoed with the same issue but did not provide enough details, it was quite hard to finally locate the problem;

If possible, could you please refer to the following suggestions:

1. What are the model number as well as the firmware version? Was it also Deco M5 with firmware 5.3?
2. Can I have a picture of the network topology, such as:
3. When the Ethernet connection failed to get internet service, what was the IP address on these devices?--how to check the IP settings (https://www.tp-link.com/support/faq/841/)--a picture of it would be highly appreciated;
4. In case it was the cable& port issue, please try to switch the port and change a new cable;

 After that, you could leave me a private message for notice;

Thank you very much.

Hi There.

I'm having the same issue with the x 20.

I have purchased the three pack and my  main deco is in my office connected directly to the NBN box.

I am trying to get ethernet out to my IP cameras box but I have no internet connection.

Please advise.

I have 4 Deco routers.  The main is a Deco W3600 with SSID: Deco_EB90.  The main receives ethernet via ethernet cable from a Motorola modem.  The ethernet cable is in the #1 port on the Deco. Wifi is fine. Firmware version: 1.5.1 Build 20210204 Rel. 51225

From the #2 port on the main deco, I run ethernet cable to the #1 port on a TP-link 8 port router.  The problem is that I get no internet connection to anything that I then connect to the switch.  If I connect the switch directly to the modem, I get internet connection to other devices that I connect to the switch, so the switch is working.

For instance, with my Samsung TV, set to a wired connection, I get the message that I am connected to the local network, "but unable to connect to the internet."  If I take the Deco out from between the modem and the switch, the TV connects just fine.

I see many others are having this same problem in this thread, but I can't see that anyone has solved it.  It seems like this should be simple! So anxious to find resolution.  This is killing me.