@Zaudi 

Hello, sorry about that.

Please help confirm some details and we will try to figure it out:

1. May I have your detailed network topology/layout? What’s the operation mode of the Deco P9, is it in router mode and the WAN connection type is PPPoE? On the Deco APP, please tap “More “on the bottom right corner then go to “Advanced”, where you will see the working mode.

2. Can you please confirm how the 4 Deco units are connected, via wireless or PLC? You may confirm it as below:
On the Deco app, click on the Internet icon, then click on one of the satellite Deco, and you will see the satellite Deco’s signal source. If there is a Wi-Fi icon on the signal source, it means the satellite Deco is using the Wi-Fi backhaul. If there is a Powerline icon, it means the satellite Deco is using PLC backhaul. Please ensure that both the two Deco P9 units are plugged into the wall socket directly but not to power extensions.

3. How often does the disconnection issue happen and how do you make it back to work? When the internet drops, how about the LEDs on all the P9s, are all flashing red?

Below are some suggestions you can give it a go.
1. Relocate the Deco nodes.
2. Swap the locations of the Deco, setup one satellite Deco to the main Deco.

3. Ensure the firmware of all the 4 Deco P9s is up-to-date.

Good days.