I am really struggling with an issue with the RT-AX58U. I have recently bought it, connected it all up and found I could not access the internet. After some time fiddling about, I noticed that my landline was not working. I discovered that every time I plugged the WAN line into the router, my landline stopped working. It does not matter whether the router is powered or not. I have a dual-socket at my house. The top socket connects to BT broadband whilst the bottom socket connects my landline. It seems the ASUS router switched both of these off therefore I couldn't access the internet or my landline. I thought, at first, that there was some fault with the router. I returned it and received the replacement today but I am getting exactly the same problem. My current NETGEAR router works fine so I'm really at a loss to understand what the issue is. I have contacted ASUS support but they have not been much help. Any ideas would be gratefully received.