Your iPhone depends on your carrier for calls, text messages, mobile data, and Personal Hotspot, so cellular problems can be some of the most frustrating issues to troubleshoot. After installing iOS 27, some users may notice their iPhone showing No Service or SOS Only, struggling to stay connected to 5G, dropping calls, or refusing to load websites over mobile data.
While these issues can sometimes be caused by a carrier outage or poor coverage, they can also result from outdated carrier settings, SIM or eSIM problems, or temporary software bugs introduced after an update. This guide walks through the most effective fixes, starting with the simplest solutions before moving on to more advanced troubleshooting.
Common Cellular Problems on iOS 27
The fixes below can help if you’re experiencing any of these issues:
- No Service or Searching
- SOS Only appears in the status bar
- Mobile data isn’t working
- Calls fail or won’t connect
- Text messages won’t send
- Slow LTE or 5G speeds
- Cellular signal keeps dropping
- Personal Hotspot isn’t working
- Cellular problems started after updating to iOS 27
1. Restart Your iPhone
Restarting your iPhone forces iOS 27 to reload its networking services and reconnect to your carrier. If your iPhone has become stuck searching for a signal or suddenly lost service after updating, this simple step often resolves the issue.
- Press and hold the Side button and either Volume button.
- Drag the power slider to turn off your iPhone.
- Wait about 30 seconds.
- Turn your iPhone back on.
- Wait a minute to see if your carrier reconnects.
2. Toggle Airplane Mode
Turning Airplane Mode on and off forces your iPhone to disconnect from and reconnect to nearby cellular towers. This can quickly resolve temporary registration problems with your carrier.
- Open Settings.
- Turn Airplane Mode on.
- Wait 15 to 30 seconds.
- Turn Airplane Mode off.
- Wait for your carrier name and signal bars to reappear.
If your iPhone was stuck on Searching or SOS Only, this is one of the quickest fixes to try.
3. Turn Cellular Data Off and Back On
If calls and texts work but websites or apps won’t load, refreshing your cellular data connection may help.
- Open Settings > Cellular.
- Turn Cellular Data off.
- Wait about 10 seconds.
- Turn Cellular Data back on.
- Test your connection in Safari or another app.
If you use Dual SIM, make sure you’ve selected the correct line for cellular data.
4. Check Your Coverage and Carrier Status
Not every cellular issue is caused by iOS 27.
If you’re indoors, underground, or in a remote location, your iPhone may simply be struggling to reach the nearest cellular tower. Try moving outdoors or to another location before continuing.
It’s also worth checking whether your carrier is experiencing a temporary outage. If family members or coworkers using the same network have also lost service, the problem is likely with the carrier rather than your iPhone.
5. Install a Carrier Settings Update
Carrier settings updates are separate from iOS updates. They’re provided by your mobile carrier and can improve network performance, calling reliability, 5G connectivity, and compatibility with newer versions of iOS.
To check for one:
- Open Settings.
- Tap General.
- Select About.
- Wait about 30 seconds.
- If prompted, tap Update.
Many users overlook carrier settings updates, but they can resolve connectivity issues without requiring a full iOS update.
6. Check Your SIM Card or eSIM
Problems with your SIM or eSIM can prevent your iPhone from connecting to your carrier, even if everything else appears to be working normally.
If you use a physical SIM:
- Turn off your iPhone.
- Remove the SIM tray.
- Check the SIM card for dust, scratches, or damage.
- Reinsert it securely.
- Turn your iPhone back on.
If you use eSIM instead:
- Open Settings > Cellular.
- Verify your cellular plan appears under SIMs or Cellular Plans.
- Make sure the line is turned on.
- If the plan is missing or inactive, contact your carrier.
7. Switch Between 5G and LTE
Some users find that their iPhone performs better on LTE than 5G in certain locations, particularly if their carrier’s 5G coverage is still expanding.
To switch network modes:
- Open Settings > Cellular.
- Tap Cellular Data Options.
- Select Voice & Data.
- Try switching between 5G Auto, 5G On, and LTE.
- Test your signal and data connection after each change.
If LTE works consistently while 5G doesn’t, the issue may be related to local carrier coverage rather than iOS 27.
8. Update to the Latest Version of iOS 27
Apple frequently fixes modem, networking, and carrier compatibility issues through software updates.
To check for updates:
- Open Settings.
- Tap General.
- Select Software Update.
- Install any available iOS 27 update.
- Restart your iPhone if prompted.
Even smaller point releases often include important bug fixes that improve connectivity.
9. Reset Network Settings
If none of the fixes above work, resetting your network settings can clear corrupted network configurations that may be preventing your iPhone from connecting properly.
- Open Settings.
- Tap General.
- Select Transfer or Reset iPhone.
- Tap Reset.
- Choose Reset Network Settings.
- Enter your passcode if prompted.
- Wait for your iPhone to restart.
This will remove:
- Saved Wi-Fi networks
- Wi-Fi passwords
- Bluetooth pairings
- VPN settings
- Cellular network preferences
Your personal data, apps, photos, and messages will not be deleted.
What if Only Mobile Data Isn’t Working?
If you can still make calls and send text messages but mobile data won’t work, double-check that Cellular Data is enabled under Settings > Cellular. If you’re using Dual SIM, verify that the correct line is selected for data.
It’s also worth checking whether you’ve exceeded your carrier’s monthly data allowance or whether data roaming has been disabled while traveling.
Why Does My iPhone Show SOS Only?
The SOS Only message means your iPhone can’t connect to your carrier’s network but can still place emergency calls where supported.
This can happen because of weak coverage, a temporary carrier outage, SIM or eSIM issues, or a software problem. Working through the fixes above will resolve most cases, but if the message persists, contact your carrier to verify your account and SIM status.
How to Tell if It’s an iOS 27 Bug
Sometimes the problem isn’t your settings or your carrier.
It may be related to iOS 27 if:
- Cellular issues began immediately after updating.
- Multiple users are reporting similar problems online.
- Restarting your iPhone temporarily restores service.
- Your carrier confirms there aren’t any outages or account issues.
If that’s the case, keep your iPhone updated. Apple regularly releases follow-up updates that improve modem stability and carrier compatibility.
When to Contact Your Carrier or Apple
If you’ve completed every troubleshooting step above and your iPhone still shows No Service, Searching, or SOS Only, it’s time to seek additional help.
Start by contacting your carrier to confirm:
- Your account is active.
- There aren’t any outages in your area.
- Your SIM or eSIM is properly provisioned.
- Your line hasn’t been suspended or restricted.
If your carrier confirms everything is working correctly, contact Apple Support. Apple can run diagnostics to determine whether your iPhone has a hardware issue affecting its cellular modem or antenna.
