i had one wifi network that was set up with
WPA2(AES), b/g/n mixed mode.
Moto G was able to recognize the network, but upon punching in the correct key, Android just complains 'Failed to connect to network'
Turns out some how if you turn the Netgear router setting page, 'WAN setting' -> set 'NAT filter' to 'open', everything works beautifully.
Netgear WTH?