There can be many reasons why extender not showing up. For instance,
a) It is plugged in far away from the router thats why extender not showing. b) Your device (mobile, laptop, tv, camera, etc) which you are trying to connect is far. c) Walls, obstacles blocking away the signal. d) Setup with the same SSID as your router Click Here to check Router Setup Page.
Follow the following steps when extender doesn’t show in your WiFi list.
Firstly, Unplugged the extender and bring it closer to the router.
If still, it is not showing up in the wifi list shut down your devices and turn them back again.
Try removing/forgetting the known wifi connections.
If you have to cover long distances you should opt for hardwire option, you won’t lose any data speed plus you will be able to cover more distance.
In this case, you will have to login into your Linksys Extender and then change the SSID from there. Note:- don’t change SSID on router otherwise your every device will get disconnected from the router.