If your Samsung Galaxy S25+ shows "IMEI null" or a "not registered on network" error, you won't be able to make calls, send texts, or use mobile data. The IMEI is a unique 15-digit code that identifies your phone to your carrier. When it's corrupted or unreadable, your device becomes invisible to cell towers.
You can check your IMEI by opening the phone dialer and entering *#06#. If you see "null" or a string of zeros instead of a proper 15-digit number, your Galaxy S25+ needs attention. Try these fixes in order before considering more advanced repairs.
Restart Your Samsung Galaxy S25+
A simple restart clears temporary software glitches and triggers a fresh network registration. Hold the Side button, tap "Restart" on the screen, and wait for the phone to fully reboot. Check your connection afterward.
Toggle Airplane Mode
This forces your cellular radio to reconnect from scratch. Swipe down from the top of your screen to open the Quick Settings panel. Tap the Airplane Mode icon, wait 10 seconds, then tap it again to turn it off. This can re-establish the handshake with your carrier.
Reinsert Your SIM Card
A loose or dusty SIM can cause registration failures. Power off your phone. Use the SIM eject tool to open the tray on your Galaxy S25+, remove the SIM card, and gently clean it. Reinsert the SIM, push the tray back in firmly, and power your phone on.
Verify Your Carrier Account
The problem might be with your service, not your phone. An unpaid bill or expired prepaid plan will block network access. Log into your carrier's app or website from another device, or call customer service to confirm your account is active and in good standing.
Reset Network Settings
This clears all saved cellular, Wi-Fi, and Bluetooth configurations that could be corrupted. On your device, go to Settings > General Management > Reset > Reset network settings. Tap to confirm. Your phone will restart and attempt a clean connection to your carrier.
Manually Select Network Type
Your phone might be stuck trying to connect to an unavailable network band. Go to Settings > Connections > Mobile networks > Network mode. Try selecting a different option, like "LTE/3G/2G (auto connect)" instead of "5G/LTE/3G/2G". Connecting on a lower band can bypass the error.
Install Software Updates
Outdated software can have known network bugs that are fixed in updates. Go to Settings > Software update and tap "Download and install". Follow the prompts to install any available updates, as they often contain critical connectivity patches for your phone.
Clear the Phone App Cache
The Phone app manages your connection to the cellular network. A corrupted cache here can cause issues. Go to Settings > Apps > Phone > Storage. Tap "Clear cache". This does not delete contacts or call logs. Restart your phone after doing this.
Test With a Different SIM Card
Your SIM card itself could be damaged. Borrow a known-working SIM from another phone and insert it into your Galaxy S25+. If the new SIM connects normally, contact your carrier for a SIM replacement. If it also fails, the issue is with your phone's hardware or software.
Perform a Factory Reset
This is a last resort. A factory reset erases all data and returns the phone to its original state. Back up everything important first. Then, go to Settings > General Management > Reset > Factory data reset and follow the prompts. If the network error remains after a full reset, there is likely a hardware issue with the phone's radio, and you should seek professional repair.