@Zaherg Yes, it appears you've got defective unit. You did all the right tests to prove that.

@Cazza1 It is valid recommendation to make M9 Plus your Main Deco. You should do that. Also, the rest of M9 Plus should become backbone of your WiFi mesh, with M5s extending WiFi from M9s to further...

@Hispanico It is possible to set static IP for that device, but not with Deco app. I run Deco mesh in Access Point mode, too. I have more than one device with static IP address. Your Deco mesh must...

@Hispanico See How to configure Address Reservation on a Deco This will only be available if you run Deco mesh in its default Router mode. If you configured Deco mesh to run in Access Point mode, you...

@siskin This may sound illogical at first, but you should check the Ethernet link between the switch and Main Deco. Something may be wrong with it. Detailed explanaiton from similar case can be found...

@sghatuwa This connection is supported. I run at my house Deco mesh consisting of M5 and M9 Plus Deco units. They run together just fine. It is recommended to make M9 Plus your new Main Deco, because...