Hi, I have recently setup three P9 deco units to provide WiFi coverage in the house and a cabin in the garden. The main unit in the house is connected to the ISP modem with other unit in the house connected via WiFi. I then have the third unit in the cabin connected via ethernet backhaul to the main unit, this is via a TP-link TL-SG1008 unmanaged switch. After configuring the primary WiFi everything was fine and I could roam between each unit. I've then configured the guest network which works ok if I connect when next to the main Deco, but if I'm near either of the other deco units, my device either times out waiting for an IP address, or if it does appear to connect, I can't access the internet. 

Reading through these forums it appears that Ethernet backhaul and using the guest network was an issue for some Deco models, but is now fixed.

Any help appreciated, as it's essential I can configure a guest network that is accessible on the Deco P9 connected via ethernet backhaul in the cabin. If not I'll have to return the units and look for an alternative.