I have a Deco X4300 Pro mesh network set up and running in Router mode with one base connected an Arris S33 cable modem using the 2.5Gbps port. With this are two Deco satellites which connect to the base via wifi. Everything runs great when this is the only configuration.

However, when I try to connect a TP Link TL-SG108 8-port gigabit switch to the Deco base using the 1Gbps port, the entire mesh network consistently goes down and won't come back up until I disconnect the switch. In some cases the mesh network will stay up and running for a short time after connecting the switch, but then inevitably goes down.

In a non-technical description, it almost feels like the base decides to try and use the 1Gbps port (that the switch is connected to) as the port it should try and obtain its internet signal from instead of using the 2.5Gbps port (where the cable modem is connected).

Has anyone experienced this or have any suggestions on what to try?

Thank you in advance.