it is most likely due to a bad implementation of the security algorithm you are using for the signal eg WEP128, AES256. the Wifi card and the Router implementation of any algorithm must match. MOST routers are now dual signal, thus they can usually transmit an older b,g,N signal alongside the newer AC2.4/5ghz signals. you just need to enable the older GUEST wifi signal. this wont affect the newer signals. You may already have this feature or if your router is actually OLD b,g,N anyway then you may have the opposite problem where the pc is expecting only Newer faster 2.4/5ghz signals and is a bit poor at backward compatibility. try finding out the make and model of ROUTER you have and the make/model of Wifi card in your pc. and which xbox you have and then we can work out whats not matching.