@Darnok 

Hi, may I know the model number of your main ISP router?

Did M4 work on the access point mode?

Was the MAC connected to the main Deco, or the 2^nd or 3^rd auxiliary Deco?

Were you able to reproduce the same issue every time unplugging the MAC？

Thank you very much.

@TP-Link 

Hey!

Yes, I'm always able to reproduce it by unplugging the auxiliary deco M4 (which my computer is connected to). Then it all starts to work again. My ISP router is Huawei HS8546V. Just to clear this out - this router is connected to every deco via ethernet. They are not directly connected in any sense. M4 work in access_point mode. I've put my main deco into DMZ on the Huawei router but still has the same issue. I also noticed that I needed wifi connection for the first setup - seems like they were having problems with discovering themselves via LAN. But they all got the ip address.

@Darnok 

Hi, thanks for the update.

Just to be clear:

 The network topology is kind like this:

Once you manually unplug MAC from Auxiliary Deco M4, all Deco M4(the main +2 Auxiliary Decos) started to blink red.

It would not auto recover automatically until the MAC Is plugged back?

Would restarting the main Deco get the connection back?

May I know the model number and operating system of your MacBook?

Later I would like to forward your case to the senior engineers for further assistance.

Thank you very much.

Thank you for looking at this case! Yes, topology is correct

>Once you manually unplug MAC from Auxiliary Deco M4, all Deco M4(the main +2 Auxiliary Decos) started to blink red.

Yes - auxiliaries are down

>It would not auto recover automatically until the MAC Is plugged back?

Yes

>Would restarting the main Deco get the connection back?

 Nope - auxiliary has to be restarted

> May I know the model number and operating system of your MacBook?

Macbook Pro M1

>Later I would like to forward your case to the senior engineers for further assistance.

Thank you!