Xperia z 5.1.1 WiFi problem

[Desmond1]

I have upgraded my xperia z to lollipop 5.1.1.after that I can't access WiFi network from my college. The WiFi is getting connected but shows a symbol like(!) on the WiFi symbol and can't access it.so I hope I will get a positive reply for this

[_alexdon_]

See this:

/t5/Xperia-Z3/WiFi-Exclamation-Mark/m-p/1008533#M186

[Phy]

Forget your college's WiFi and re-add it

1. Settings 
2. WiFi
3. Long press on your college's WiFi
4. Forget 
5. Restart the phone
6. Scan and add the WiFi

[davidcorredor]

can you solve it? i try flashing my device and installed another rom.   i want to downgrade my phone

[Desmond1]

I tried this and again negative response.I think android 5.1.1 has this problem. I have faced this problem after I upgraded to 5.1

[Desmond1]

Or anyone please suggest me a genuine Android KitKat firmware to downgrade my xperia z

[rajanv]

I had this issue first when I upgraded to Android Lollipop way back in May on my Xperia ZR. The phone lost all contact with any wireless network in the 2.4 ghz range. To overcome, for a few months, till about 2 days ago, I used the 5 ghz band. That worked well and fortunately, I had a router that supported it.

Now, after the last upgrade to 5.1.1, I too have the problem of 2.4 ghz networks, appearing, but still not being able to connect to them. Finally, I decided to go the Cyanogen Mod way. I unlocked my bootloader, but did not save the device keys. There are instructions on the internet to save the device keys before unlock of bootloader, which I failed to find or perform. I then downloaded Cyanogen Mod 12.1 and installed it following the instructions on the Cyanogen Mod page for Sony Xperia ZR.

After I installed Cyanogen Mod 12.1 for dogo, I found that 2.4 ghz band networks are visible and connect very well. I thought this was a hardware issue, but I am now convinced that Sony needs to do more testing before releasing firmware upgrades.

[Desmond1]

Rajanv, I didn't understand what did u saidsaid.what is cyanogen mod?
My problem is that only I can't access WiFi from my college after upgraded to 5.1.1.but I can access WiFi from my residence. There is problem with college WiFi connection

[RolloM]

Cyanogen is an alternative software for your phone out there, which some nerds use. As a person who does not know what this is I would not use it. It would cost you weeks to unterstand how to do it.

I have similar problems with my z3 compact here, version 5.1.1, and it looks like Sony has been having wifi problems for years, and we are just the next series of victims... There are about a dozen tips out there how to fix it, but they dont work. Because the phone is broken, the settings are completely ok. Some people tell us that disabling Bluetooth might solve the problem. But hey, then Bluetooth is broken...

[BF68]

I have the same issue. Sinne the upgrade to 5.1.1 WLAN didn't work any more. Now I figured out that I can solle the issue by deactivating Bluetooth!