So I ordered a x92 smart tv box and I installed it but when I turned it on and went into settings it couldn't find my sisters wifi
(who lives 1 floor below me) even though my phone and every other phone picked it up with 100% signal strength?
It found a whole lot of other wifi networks but for some reason my sisters wifi won't even show up with any kind of signal
so I'm wondering what the hell it could be?

My sisters router is a ASUS RT-AC53 and I also installed Netgear WN3000RP v2 (wifi extender)

Any help would be greatly appreciated!