Hmm, it sounds like this is more an issue with the router for that network rather than your machine. Overlooking this, it could mean that you laptop has a VERY old wireless card and it simply doesn't understand the higher levels of security.
I know that this doesn't really help you, but if you are using a card that only understands older network security, then either the router/wifi extender will have to be changed, or you will need a more up to date network card; of course, with it being in a laptop, this is far more tricky than if it was in a pc. Like I say, it's not the most helpful answer in the world, but hopefully it can shed some light on the issue.
http://www.howtogeek.com/167783/htg-explains-the-difference-between-wep-wpa-and-wpa2-wireless-encryption-and-why-it-matters/
Other than that, I'd still say that it is a problem with the network, and not with you, but best of luck