@SVRich 

Hello, we need to do some troubleshooting first to locate the issue so that we can try to fix it later. 

1. What is the current network diagram?

2. What is the led status of the Deco M4s when you lost connection? How do you make it back to work after that?

3. At that time, with a computer connected to the main Deco directly, can you access the internet? Try to simplify the network diagram, in other words, connect the main Deco to the modem only and then connect your computer to the main Deco to verify whether it works well.

5. Besides, you can try to relocate them and swap the locations of Deco units.

Thanks in advance, and have a nice day. 

@SVRich 

Hello, thanks for the update.

Do you mean the LEDs on the two Deco M4R will be solid red? If this is the case, please help check more details again and we may ask our engineer to investigate further:

1. When the LEDs on the two M4R are solid red, please launch the Deco app and check what is the IPv4 address, click on More-Advanced-IPv4, send me the screenshot.

2. Who is your ISP and what is the model number of your modem?

3. Send me the IP address info on your computer when it is connected to the modem directly.

4. What is the model number of your switch? Leave it disconnected from the network if possible, just have a test if there is anything to do with it.

Thanks.

@SVRich 

Thanks for the update.

We have recently released a new firmware for the Deco M4, you may update it and monitor.

Good day.