Using ethernet to connect access point to router
I am trying to connect my range extender (RE220 AC750) to my router via an Ethernet cable in order to get better signal in the basement, but when I do the router becomes unavailable to my devices and the range extender, the range extender still has an internet connection (an incredibly stable one at that) but acts as if its not getting any signal.
I need to do it this way because if the range extender was put somewhere where it could connect to the WiFi it likely wouldn't have much better signal downstairs than the router itself, and the only place worth putting it is downstairs where I can then connect multiple devices as needed.
There is also the side effect of it preventing me from being able to connect to the main router upstairs which is a pretty big issue.
if there are any further details you need then ask and I will reply when I can, any help or advice would be appreciated.