Hi Daniele,
I tried to reply to this yesterday but not sure if I sent it through correctly. I purchased a switch (non managed as this was the variety that was recommended for home use and non technical people like me. I installed it all yesterday and removed the connection to the 4th port and put all additional devices onto the switch. Unfortunately, I have exactly the same issue. Only I device seems to be working on the switch the other devices have the same message if I look under the network setting ie that the router is self assigned and can not connect to the internet.
Is there some setting or something additional that I need to do to activate the additional ports so that they get a router setting.
Thanks you in advance for you support .