Are your Deco P9s running in access point mode? I have found that access point mode does not work with the Deco P9s.

I have set them up like this:

Modem > PPPoE into Router (not wifi enabled) > RJ-45 into Deco P9.

2x Deco P9 connected by just plugging them into the wall socket electric (for the PLC).

This setup did not work in access point mode but when changed router mode and the network change to:

Modem > PPPoE Deco P9

2x Deco P9 plugged into wall socket electrics.

This did work. firmware 1.0.1

@BozMoz 

Thanks for your reply. 
 

I have always used my network exactly as you mentioned last. So with the P9 in router mode. Strange thing is that the network did work for about 2 days and then suddenly it stopped. 

After exchanging the units the network works fine again, but the ethernet Port nr 1 of the first main unit stopped functioning permanently. This unit is now last in the chain.

@Kevin_Z 

Hi,

thank you for your help. I followed your instructions, and indeed Port 1 does not respond. Port 2 works fine, showing ip address and all, including 1 Gbit/sec (!) connection speed. 

I will contact my retailer for a replacement.

One question on this; Since the system is a 3-pack, is it possible to replace just one unit, or do all units need replacement? In other words, does the system keep on working if you replace one? I am asking this because I feel a bit reluctant to pack and send the whole system (with at least 2 perfectly functioning units), wait for the new one to arrive and then have to install everything again. 
 

Thanks in advance