Overview #
If your Android phone suddenly stops receiving calls or texts — while others nearby have service — the issue is likely a SIM card, carrier registration, or network configuration problem.
This guide helps you determine whether the problem is with your device, SIM, or carrier, and gives you proven steps to get your signal and messaging working again.
What you’ll learn
- How to check signal strength and SIM registration
- How to refresh mobile network connections
- How to clear messaging app data and reset APN settings
- How to verify carrier account status
Estimated time: 10–25 minutes
Skill level: Beginner–Intermediate
Terms and Definitions #
| Term | Meaning |
|---|---|
| SIM Card | Small chip that connects your phone to your carrier’s network |
| APN (Access Point Name) | Settings that define how your phone connects to the internet and MMS |
| LTE / 5G | Cellular data standards for faster connections |
| IMEI | Unique hardware identifier used by your carrier to register your device |
| VoLTE | Voice over LTE — allows calls over the 4G network |
Steps #
Step 1 — Check Signal and Airplane Mode #
Start with the basics.
Look at the signal bars on your phone — if there’s an “X” or “No service,” it’s a network or SIM issue.
- Swipe down → ensure Airplane Mode is off.
- Toggle Airplane Mode on, wait 10 seconds, then off again — this forces the phone to re-register with your carrier.
- Try calling or texting yourself from another device.
Step 2 — Verify SIM Card Detection #
Go to:
Settings → About phone → SIM status.
Check that it shows:
- Network: your carrier’s name
- Signal strength: numerical value (e.g., –85 dBm is good)
- Mobile voice network type: LTE / 5G
If it says “No SIM” or “Invalid SIM”:
- Power off the device.
- Remove the SIM, clean it gently with a soft cloth, and reinsert.
- If it still fails, try the SIM in another phone to verify if it’s functional.
Step 3 — Reset Mobile Network Settings #
Settings → System → Reset → Reset Wi-Fi, Mobile & Bluetooth.
This clears network configurations, APN profiles, and carrier settings.
Reboot your phone afterward and let it auto-detect the carrier again.
Step 4 — Check for Carrier or Account Issues #
Sometimes carriers suspend service for billing or SIM reactivation delays.
- Log into your carrier’s app or website.
- Check your account status and active line.
- If needed, contact support to re-provision your SIM.
You can also dial:
*#06#
to verify your IMEI number.
Provide this to your carrier if they need to reactivate your device.
Step 5 — Re-register Network Connection #
Settings → Network & Internet → Mobile network → Automatically select network.
Toggle it off, wait a few seconds, then on again.
If still no signal:
- Disable automatic selection.
- Manually choose your carrier (e.g., Verizon, AT&T, T-Mobile).
- Reboot your phone after saving.
Advanced (ADB command):
adb shell service call phone 1
This reinitializes the radio and forces re-registration.
Step 6 — Check APN (Access Point Name) Settings #
If texts or picture messages (MMS) aren’t sending or receiving:
Settings → Network & Internet → Mobile network → Access Point Names.
Tap your carrier and verify:
- APN: matches your carrier’s official configuration
- MMSC & MMS proxy: correct values
- APN type: default,supl,mms
If missing, tap Add → Reset to default.
Step 7 — Clear Phone and Messaging App Cache #
For text issues only:
- Settings → Apps → Messages → Storage & cache → Clear cache / Clear storage.
- Reopen the Messages app and allow permissions.
- Send yourself a test text.
Optional ADB reset:
adb shell pm clear com.google.android.apps.messaging
Step 8 — Verify VoLTE or 5G Calling #
Settings → Network & Internet → Mobile network → Advanced → VoLTE calls.
Ensure it’s enabled.
Some carriers no longer support older 3G calling, so disabling VoLTE can cause dropped or missing calls.
Step 9 — Check for SIM Profile Corruption #
If your SIM is detected but not functioning correctly:
- Try the SIM in another device.
- If it works there, your phone’s SIM profile may be corrupted.
- Ask your carrier for a replacement SIM — most provide one free of charge.
Step 10 — Check for Firmware Updates #
Firmware updates often fix modem or radio issues.
Settings → System → System update → Check for updates.
Install all available updates and reboot.
If you’re using a rooted or custom ROM device, flash the latest radio/modem firmware manually.
Verification #
| Check | Action | Expected Result |
|---|---|---|
| SIM detection | Settings → SIM status | Shows carrier and signal |
| Network registration | Airplane toggle | Signal reappears |
| APN verified | Matches carrier | MMS and mobile data work |
| Calls & texts | Tested | Normal communication restored |
Conclusion #
When your Android can’t receive calls or texts, the problem almost always lies in network registration or SIM provisioning — not a broken phone.
By reseating your SIM, resetting network settings, and verifying APN and carrier status, you can restore full functionality quickly.
If the issue persists after trying these steps, a replacement SIM card or carrier-side refresh will typically resolve it.
