Q: ios 9.3 can't connect to wifi or data

Take a look at this Apple Support article:

https://support.apple.com/en-us/HT204051

Reset your network settings.

Settings - General - Reset - Reset Network Settings

Reset your device. This won't delete your data stored on the phone.

• Press and hold the Sleep/Wake button
• Press and hold on the Home button
• Keep holding both buttons until the display turns off and back on with Apple logo on it.

Alternatively, you may go to Settings - General - Reset - Reset All Settings

Same exact problem as described on an iPhone 6+ after the 9.3 upgrade.  After the upgrade I get a notification from the phone to verify my iCloud account, tried that but I keep getting "error connecting to the Apple ID server".  I try turning off wifi (using LTE through AT&T) and I get the same thing.  In LTE and wifi I see the same behavior with some apps (Facebook) receiving notifications to the phone while a lot of stuff (iCloud, Speediest, Safari) can't access the internet. I did try to reset the network setting and no dice.  I was going to downgrade to 9.2.x but I can't because "Find my iPhone" is turned on which, of course, I can't turn off because iCloud can't verify with the server.

It is an endless loop and unacceptable.

I finally got something that worked.  I did call Apple Support and they said to boot the phone into recovery mode and then do a restore that way.  To do this turn off your phone.  On your Mac (or PC) open iTunes and as you connect your iPhone to the Mac hold the home button until you see the "connect to iTunes" symbol.  From there iTunes will notice you are in recovery mode and will then ask you if you want to do a restore.

The explanation (that I'm not buying) was that the download was somehow corrupted.  I should also point out that I couldn't simply do a normal restore from iTunes because it would force me to turn off "Find my iPhone" on my phone which I can't do because the phone can't connect to iCloud.

Anyway, once I did this I'm back on my feet with 9.3

I spoke too soon.  It looked like the recovery mode option was going to work but I'm exactly back where I am.  Can't enter my iCloud credentials, can't use Safari, basically the phone is just that.  A phone.

Hi

Go to settings reset network settings .

After reset enter your router wireless key .

Also go to itunes main page bottom of page apple ID

Sign out then sign back in .

Cheers

Brian

Hi there. I had the same problem. Wifi and cellular was locked out after upgrading to 9.3..... The problem was related to Disconnect, an adblocking app I had installed a few months ago. After disabling on demand access in its settings the updated phone worked fine. In fact, I just uninstalled Disconnect entirely and all is now well....

I recommend having a look at your phone and seeing if there may be conflicting third party apps.

o1sound, thanks this resolved my issue.

Did you guys disable ad blocking or just uninstall the ad blocker?  I had 1block installed and I removed it, restarted my iPhone and it still isn't working.

OMG I have been having the same issue, and I don't have any ad blockers installed.   If I am not on wifi nothing will connect.  It's like I don't have data on my phone at all.  Has anybody found a solution for this.  Hopefully Apple releases another update soon that will fix this issue.

oh, man, i wasted several hours trying to fix this...and apparently the Disconnect app was blocking it all....life's too short for this!!

thanks so much o1sound.

So my solutions turned out to be really painful but it works.  I booted into recover mode, again.  Restored the iPhone, again. 

However, this time I did it as a new phone and I'll just have to manually reinstall apps, assuming one of the many I had was the culprit.  I did uninstall the one ad-blocker I had and any other apps I suspected might get in Safari's way and that didn't work.

So if you are having the problem, my guess is there is a 3rd party app or possibly a setting Safari tripping you up and if you can't find it then this will definitely get you back on your feet even if it does take a year off your life.

The same here. I deleted the vpn profile and "disconnect app" and everything started to work. In my case the phone was trying to connect to a VPN network due to that app. Deleted the app and the vpn profile and I could connect. Now everything to seems work fine. Thanks for the tip.