Hi David,   thanks for your help.   Yes I have FTTP. I have assigned a static address for the Synology NAS of 192.168.1.2. The NAS is directly attached to the Archer via ethernet I normally use an Orbi system for my WiFi, however I have turned it off and have gone back to to the Archer Wifi but this did not change the behaviour. I have a Denon and Yamaha AVr and a Control4 home automation system attached to the LAN. I have switched off (at the power point) all of these in case there was something causing a problem there, but has not changed the problem.   The process I am following is from this Youtube video https://www.youtube.com/watch?v=STlKmQE5luM&t=931s At 5:25 it shows the process to setup the router. It is at this point that I get the error message. I have included a jpeg of the screen at the failure point.   Cheers,   David ... View more