Hi!, Seeing the behavior on mine (EX2 Ultra) i saw that, when the Ethernet plug goes out. the status led goes Solid Red. This could mean that “Solid Red = No network connection” (the leds behind the NAS surely are off).
Check if both end of the ethernet cable are well plugged an, if they are well plugged, that the cable works properly (use an ethernet cable tester). If everything goes ok, but keeps with solid red, check your switch/router ethernet port (where your NAS is connected). If all works, but your NAS keeps with solid red, then maybe the ethernet port of your nas is damaged, and need service. Do a last test using a crossover cable from your NAS to your PC, if the NAS was using an static IP, change your PC IP, so it can be in the same subnet, if the NAS was using dhcp, then you need to set a dhcp server. In that case, is up to you to check how to do that (google is your friend n_0).
If you determine that the ethernet port is damaged, or you can link the NAS (the ethernet leds powers on) but the status led keeps showing solid red, take your unit to service, o claim your warranty if apply.