Z2 tablet - wifi issue

[Neolith]

I have a 16G wifi only z2 tablet and have a repeaatable wifi problem.

The tablet will connect without issue initially and performs brilliantly, if however the wifi connection is lost it will often go into an "unrecoverable" state. There are 2 scenarios it seems:-

1) wifi connection shown as active on status bar but no communication actually happening.

2) no wifi connection and attempts to "connect" report "authentication problem"

from scenario 1 toggling wifi or otherwiese forcing a reconnect will result in scenario 2

There is no recovery from this that i have been able to find. Rebooting the tablet will fully restore the connection and everything is fine, but clearly for a wifi only device having to reboot everytime you want to reconnect is a pain in the bum. (forgetting the connection and other such things make no difference, only a reboot seems to fix it)

I reported this to live chat support and was advised to use the pc tools to "repair". This was done, but to no avail, they then advised that the device needed to be returned to the factory for a repair. as the tablet was only 7 days old i returned to john lewis nad exchanged it for another. Needless to say this new tablet has the exact same issue. I don't think for a moment this  is a device specific hardware fault, it seems far more like an issue with caching the connection details.

I have followed the advice elsewhere on here for diagnosing wifi issues, they makeno difference. I can reproduce the issue with 3 networks, the first was a netgear (which I then bricked whle updating 😞 ) . I replaced this with a high end asus wifi router and whilst it made my speeds rcket the connection issue remains. I have a Huawei mobile wifi (mifi) which is on T-mobile and have the same issue. 

My Z1 phone, my wife's samsung phone, my daugters' Nexus 7 and HUDL tablets all work perfectly, as did my previous tablet (asus TF700) this is a Z2 tablet issue, i am certain, though more than happy to have that viewpoint tested. 🙂

I don't yet have any 100% certain steps to reproduce, been to busy to diagnose fully, however tonight i was using the mifi network and the mifi unit ran out of power, plugging it in and turning it back on again restored all the other devices' connectivity but the z2 showed the "authentication problem" error, needless to say,, rebooting the z2 brought it back online as well.

Any thoughts and advice most welcome.

i'm on the latest 314 build. With the first device i was using the smart band but on the new replacement one i have not. I have nt been using stamina mode. Not sure what else to add at this stage...

regards 

Neil

[SergioPL1]

1) First check Wifi / Advanced settings - check if you have "Always on" setting. I had a lot of power and connectivity issues on Xperia P and Z with different setting here. It carrier over devices with gmail account so start here.

2) Which band you use? It shouldn't matter but for diagnostic purpouses it's worth noting. 2.4 GHz or 5 GHz? Higher band is faster but it's very susceptible to low reception quality and may refuse connection to low power networks and in hotels.

3) Which type of security you use? I'm using my tablet often within WPA2-PSK with AES encryption (Asus N66U router) and WPA2-Enterprise without any issues. 

4) Have you been playing with default 'advanced' settings in your routers like beacon size, keys reneval interval and so on? I had some issues with non-default settings on many PC's and US Robotics APs.

5) Some combination of devices just doesn't work. Not that I want to say Sony is fine here but I have a Cisco WAP4410N devices in my office. They cause a lot of troubles that are hard to troubleshoot. They refused to work with MacBooks under OS X 10.7+ while worked fine with the same machines using Windows7 under bootcamp. A year later Cisco released updated firmware that resolved the issue. Now I have a problem with Lenovo X1 Carbon (and other Haswell based ultrabooks) with those devices while other devices work fine. Devices connect, work for some time and... never connect again or say they work fine with full network level but no real transmision occurs (ping, dhcp fails). Maybe it's that one case that your set of devices causes troubles with Z2 Tablet? My refused to work with hotspot mode of Xperia Z1 for no real reason but worked fine a month or two ago with the same firmwares.

I would start with checking connectivity using some set of tools like iPerf (to transfer a lot of data and measure real bandwidth), Wifi Analyzer to check network level and of course Ping to test basic connectivity. But start from setting "Wifi Always on when screen off" in Wifi Advanced settings in your Z2 Tablet.

[Kovikshamn]

Hi

I got the very same problem after FW update to 314 build yesterday. Before that it worked perfectly with different networks selected automaticly. Have tried the first advises in the first reply but without success. Is it possible to "undo" the latest FW update?

Regards K

[Neolith]

Thanks for taking the time to write a constructive reply. I am not at hom right now so can't test on my asus router but i'm using the huawei mifi adpator and have been using free wifi services over and all exhibit the exact same problems.

Always on is set I've not touched any advanced settings in fact, factory resets and so forth have not fixed this.

I noticed that in other posts you appeared to be awaiyting the 314 upgrade. it will be intersting to see if you experience these issues that I see when you get it (unless i am misreading the pther posts and those aer out of date posts)

my security seems to match yours wpa2-psk withh aes

My Mifi adaptor only supports 2.4 but my ASUS router supports both. 2.4 and 5  Ghz I see the exact same issue with all of these as well as with other wifi hotspots when i'm in cafes etc. I've only recently bought the Asus router and as such it is running with default settings 

basic connectivry works when the wifi is setup. this is not so much a network connectivity issue as a problem with establishing a first hop route to the wifi network itself. As such first time after a reboot allwill be perfect and very fast compared o my older devices, 30mbps on my asus router. but subsequent attempts to connect will fail and no IP address will be assined., no default gateway established etc so needless to say pings and the like will fail.

signal strength is fine reportin as excellent and wifi analyser has no issues showing.

Good luck with getting 314 upgrade but I hope when it comes it does not leave you with a worse network behaviour like I have at ppresent.

regards

Neil