In order to reconnect to Mywifiext using Ethernet Cables, you need to keep your extender close to your router, connect it with the help of the Ethernet cables and then launch a web browser on your device. Type the site address or IP of the extender and then go to the login page. On the login page enter the changed credentials that you may or may not have changed later. Once you press login you will be on the setup site and can reconnect the extender.

https://extenderhelp.net/