"Data was just working fine but then all of a sudden, it stopped working since the other day, following upgrade to new version of Android 4.1.2 using OTA update on my phone. There's nothing wrong with text and calls though. Sometimes when I tried to make a call, the 4G network displays in the notification menu on top of the screen, and then it disappears. I also noticed that without Wi-Fi data will not work, yet the Wi-Fi works fine. I've called my service provider/carrier and notified them about my problem."
Data issues are most likely due to the following reasons:
- Device does not connect to the data network including your service area.
- Device settings configuration error.
- Network connections error.
- * Reset the APN (as instructed by carrier) - no good
- * Manual network search and selected carrier - still no data
- * Reset the phone for several times - no good
- * Remove the SIM and restarted the phone with and without SIM - no good
- * Turned Airplane mode ON and OFF - still data won't work
1. Open the phone dialer.
2. Press ##72786#
Hint: When you keyed in these numbers on your Galaxy S3, all data will be wiped off your phone. Having this said, we suggest creating a backup first.
3. Reboot the phone and reprovision. You may need to contact your service provider or carrier for reprovisioning of the device, including the modem/wireless router.
If problem persists, try to change the Network Mode from LTE/CDMA to CDMA, and then reboot the phone. Otherwise, do the following steps:
1. Go to Settings.
2. Select More Settings.
3. Go to Mobile Networks.
4. Select Access Point Names, and then create another (new) APN with a different name. Retain same values of your original or default settings such as APN, proxy, port, username, and password. In short, the only thing that's changed is the APN name which is already new.
5. Select your newly created APN.
6. Restart the phone, and then try to see if mobile data is back.
APN or Access Point Names Settings refers to a setting that is only applicable or available on GSM/HSDPA/LTE networks, including those operated in the United States by AT&T and T-Mobile. If you don't see APN settings on your device, then it indicates that this setting not applicable to you.
If problem persists after performing the above steps, then proceed with the following:
1. Go to your account dashboard on your phone.
2. Turn off or uncheck the box next to the optiont that says, "Allow to connect to Internet." Doing so will let your phone do an automatic PRL update.
3. Restart the phone.
4. Now get back to your account dashboard and switch it back to allow your phone to connect to the Internet. Just check the box next to the option that says so, and then hit Save.
5. Go to your Mobile data settings and set the preferred mobile network to CDMA/LTE.
6. Restart the phone.
This procedure works for some GS3 users having the same data network issue. Hope it will do good for you too.