When the network status indicator on your BlackBerry reads "SOS," your phone cannot connect to your cellular network. In this state, you can't place or receive regular calls or texts, but emergency calls -- such as to 911 -- may still work. A wide range of situations can cause SOS mode, ranging from physical damage to incorrect settings. To resolve the problem, check each of the potential causes and solutions. If nothing solves the problem, contact your provider for further assistance.
SIM Card Problems
If you use your BlackBerry through a GSM network -- such as AT&T or T-Mobile in the U.S. -- the phone relies on a SIM card containing your account information. A loose or damaged card can lead to an SOS error. Turn off the phone, pull out the battery and take out the SIM card. Check the card for any signs of damage, such as scratches or corrosion. Reinsert the card and battery and try the phone again. You can also try the card in another BlackBerry to check if the card works. If it does not, ask your carrier for a replacement.
Network Service Problems
You may see an SOS error when outside the range of your carrier's network. This is normal behavior, and your phone will automatically regain service when you enter a covered area. The same problem will occur if the carrier has turned off service to your BlackBerry. In this case, contact the provider to regain use of the phone.
Network Selection Problems
You will see the SOS indicator if your phone connects to an alternate network that doesn't support roaming, or if you have your network mode set to "Manual" with no network selected. Try disconnecting and reconnecting to the network. If that doesn't help, reboot the phone. If the phone remains in SOS mode, open "Options" and "Network." If the mode is set to "Manual," change it to "Automatic." If it's already set to "Automatic," or if that doesn't fix the problem, set the mode to "Manual," press "Scan for Available Networks" and choose a wireless network.
CDMA WorldPhone Problems
WorldPhone editions of BlackBerry phones have a Network Technology setting that switches between types of cell networks. If it's set incorrectly for the network you're trying to use, the SOS error will appear. Open "Options" and pick "Mobile Network." Switch the Network Technology option to the opposite setting -- either "Global" or "1XEV" -- to try and resolve the problem.
Updating the Phone
An outdated version of the phone's operating system may cause network problems. To update your BlackBerry, connect it to a computer with the BlackBerry Desktop Software installed. In the program, click "Update" to check for updates. If one exists, press "Get Update." Check "Back Up Your Device Data" if you want to save a copy of your settings, emails and other data, and then press "Install Update" to update your phone.