Have you tried resetting the Network Settings?
1 - Reset network settings by selecting Settings > General > Reset > *Reset Network Settings*.
Note: This will reset all network settings, including passwords, VPN, and APN settings.
2 - Restart the device. Hold the power button until "slide to power off" appears. Slide to power off your device. When it is off, press the power button to turn it back on.
I have a similar problem. My iPad just stopped connecting to 3G five days ago. Everything worked fine before. Now I get "could not activate cellular data network" and "a data connection is not currently allowed". I have tried resetting the network settings, restarting the iPad, take out the SIM card, change flight mode settings and talked to my operator Comviq. Nothing works...
I have read there might be problems with 4.2.1. Does anybody know if this might be the problem we have? If so, how do I change to anther OS?
Hello, I hope you still read this post even after so long time, but I have the same problem you mention and I was wondering if you succeeded to solve it. I tried every possibility to reset, including a full reset and I have already tried a new sim card.
The problem still remains. Does anyone has an idea?
Thanks in advance.