iPad 4 not connecting to WiFi network

[neartheredrocks]

I have two iPads in front of me - mine (iPad 3, WiFi only) and a friend's (iPad 4, WiFi and 3G). The iPad 4 has no data plan yet. Both iPads have iOS 6.0.1.

My iPad is and stays connected to my WiFi network (as well as my iMac and two MacBooks) but the iPad 4 looses the connection all the time and very often does not even join the network (message: "Unable to join the network xxx"). This is basically true for both of my networks (2.4 GHz and 5 GHz). It works somehow better for the 2.4 GHz network and is very bad with the 5 GHz network). Restarting the iPad does not help.

What I also notice is that the iPad 4 is seeing less available networks than the iPad 3 (but it always sees both of my networks).

Any idea what might be wrong here and how it can be fixed? I know there is already an iOS 6.0.2 but as far as I know it is only for the iPad mini and the iPhone 5 and anyway my iPads here say that the software is up to date with iOS 6.0.1 and an update is not possible.

 

[AQ_OC]

Reset the network settings...,

 

[neartheredrocks]

Reset the network settings...

Doesn't make any difference. Now the iPad 4 does not connect at all anymore to the 5 GHz network, only to the 2.4 GHz network. The iPad 3 can connect to both networks and the iPad 3 is also still seeing more available networks (although by far not as many as my iMac sees - in the moment I see 3 networks on my iPad 3 and 12 on my iMac).

 

[neartheredrocks]

I deleted the networks on the router and recreated them again and now both iPads do connect to both networks. No idea why this was necessary.

 

[twerppoet]

You could have probably just restarted the router(s).

Routers can take a dislike (for lack of a better technical term) to certain devices, remembered by their unique MAC address. This is fairly common for iOS devices for some reason. Restarting the router clears the logs and buffers, giving the device a clean slate.

The other possibility is that when you recreated the networks you also reconfigured them to support the IP6 internet standard. You don't have to do this for the local network, but it needs to be supported on the WAN side.

However, all the newest iOS devices need this in order to authenticate properly, and since your iPad 4th gen was already working it seems unlikely to have been the problem.