When you have more than one Netgear extender in your home with the old router, and you want to switch the router to a new one, you should apply reset process first to the extender and then start the Netgear extender setup again. So that the extenders forget the previous data and connects with the new. But if that is not working, then you have to use some of the tips and solutions from... https://netgerext.net/wifi-extenders-cant-connect-to-new-wifi-router/