When Android shows “No SIM”, “SIM not detected”, “Invalid SIM”, or the SIM randomly disappears, the root cause is usually one of these:
- SIM is not seated properly or tray is slightly loose
- SIM contacts are dirty, SIM is damaged, or tray is bent
- Software glitch after an update
- eSIM profile issue (if you use eSIM)
- Network settings need a reset
- Your SIM needs re-provisioning or replacement by your network provider
Start here (quick diagnosis)
- Physical SIM: if it stops working after a drop, water, or frequent tray removals, it’s often hardware/SIM wear.
- eSIM: if the line is turned off, removed, or partially activated, the phone may show no SIM or no service.
- If the SIM works in another phone, your phone’s SIM slot may be the problem.
Do this first
- Restart the phone (often fixes temporary SIM glitches)
- Power off → remove SIM tray → reinsert SIM correctly → power on
- Clean SIM and tray gently (dry cloth) and try again
- Reset network settings (Wi-Fi, mobile, Bluetooth)
- If eSIM: toggle the line off/on, and only remove the eSIM profile if you can re-download it
Mobile Data Not Working on Android: 15 Fixes (Any Country)
Fix 1: Restart your phone
Samsung’s official troubleshooting for “No SIM card detected” starts with restarting.
A restart refreshes the radio and SIM services.
Fix 2: Power off before touching the SIM tray
Turn the phone OFF before removing the SIM tray. This avoids read errors and protects the tray/contacts.
Fix 3: Reseat the SIM (correct orientation matters)
Remove the tray and place the SIM flat and aligned. Even a tiny misalignment can trigger “No SIM.”
Fix 4: Clean SIM contacts and the tray (dry only)
Use a soft dry microfiber cloth. Avoid liquids. Dust, pocket lint, or light oxidation can cause intermittent detection.
Fix 5: Check the tray for bends or cracks
If the tray is slightly bent, the SIM may not press properly against the reader.
Fix 6: Try the SIM in a different phone
This is the fastest way to isolate the issue:
- If SIM fails in another phone → SIM is likely damaged and needs replacement
- If SIM works elsewhere → your phone slot/software is likely the issue
Fix 7: Try a different SIM in your phone
Borrow a working SIM (same size) and test:
- If other SIM works → your SIM is the problem
- If other SIM also fails → your phone may have a SIM slot or software issue
Fix 8: Toggle Airplane Mode on/off
Airplane mode refreshes the cellular radio and can bring the SIM back without removing it.
Fix 9: Check SIM settings (Dual SIM phones)
On dual SIM devices, make sure the SIM line is enabled in SIM settings and selected correctly for calls/data.
Fix 10: Reset Network Settings (strong fix)
This clears cellular settings that might have broken after an update. Sony’s Android guidance shows the typical path:
Settings → System → (Advanced) → Reset options → Reset network settings
Samsung also includes network-related resets in SIM troubleshooting flows.
Fix 11: Check for a system update
If the SIM issue started right after an update, check if there’s another patch available.
Fix 12: If you use eSIM, don’t delete the eSIM profile unless you can re-add it
If you remove the eSIM profile, you usually need the carrier’s QR/activation again. Samsung explains eSIM setup commonly uses a carrier QR code via SIM manager.
Google Fi’s troubleshooting also includes removing eSIM profiles and re-activating when needed.
Safer first step: toggle the eSIM line off/on.
Fix 13: If the message is “Invalid SIM”
Common reasons:
- SIM is not active (new SIM not activated yet)
- SIM is expired/blocked
- Phone is locked to a specific provider (in some regions)
Your network provider can confirm if the SIM is active and re-provision the line.
Fix 14: Replace the SIM (often the real fix)
If the SIM is old, scratched, or intermittently detected, replacing it usually solves the problem. Google Fi’s SIM troubleshooting includes removing the failed SIM and using a new SIM.
Fix 15: If nothing works, it may be hardware
If:
- multiple SIMs fail in your phone, and
- network reset + updates didn’t help
then the SIM reader or motherboard may need repair.
4G/5G Not Showing After Update on Android: 14 Fixes
Sources
Samsung Support: Fix “No SIM Card Detected” on Galaxy
www.samsung.com/uk/support/mobile-devices/how-to-fix-the-no-sim-card-detected-error-on-samsung-galaxy-devices/
Google Fi Help (Android): Troubleshoot SIM card issues
https://support.google.com/fi/answer/15518233?hl=en
Samsung Support: Using Galaxy smartphones with eSIM (QR code setup path)
https://www.samsung.com/my/support/mobile-devices/using-your-galaxy-smartphones-with-esim/
Google Fi Help (Android): eSIM setup and steps that include removing eSIM profiles
https://support.google.com/fi/answer/13390949?hl=en
Sony Support: How to reset network settings on Android (generic path)
https://www.sony-asia.com/electronics/support/articles/SX670101
