@David-TP Thanks for the response, but this problem was too disruptive so I had to return the Decos. I got an Archer AX21 instead.

I recently set up my 2 pack of X55s.THe Main Deco X55 in my living room and is connected to the WAN. I have one NAS hard-wired to this X55. There are 12 other devices on the network including IOT...