Seeing a "Not registered on network" error on your OnePlus 13 means it can't connect to your carrier's cell towers. You'll be stuck without calls, texts, or mobile data. This is a common but frustrating issue that can pop up after a software update, a change in location, or sometimes for no apparent reason at all.
Before you worry about anything serious, there's a quick fix that resolves this for a lot of people. Pull down the notification shade twice to open the Quick Settings panel and tap the Airplane Mode icon to turn it on. Wait about 15 seconds, then tap it again to turn it off. This forces your phone's modem to completely restart its connection to the network. Give it a minute to search for a signal. If you see your carrier's name reappear in the status bar, you're back in business.
Restart Your OnePlus 13
If toggling Airplane Mode didn't work, a full restart is your next best step. This clears out any temporary software glitches in OxygenOS that might be interfering with the network registration process. Just hold the power button and tap "Restart" on the screen. Wait for the phone to fully boot up before checking your signal.
For a more thorough refresh, you can perform a force restart. Press and hold the Volume Down button and the Power button together for about 10 seconds. You'll feel the phone vibrate and see the OnePlus logo. This is a hard reboot that can clear deeper system hiccups.
Check Your SIM Card
A loose or dirty SIM card is a classic culprit. Power off your OnePlus 13 first. Use the SIM ejector tool that came in the box to pop out the tray on the bottom edge. Carefully remove the SIM card and give both the gold contacts on the card and the inside of the tray slot a visual inspection.
If you see any dust or debris, gently wipe the contacts with a soft, dry cloth. Blow lightly into the tray slot to dislodge any particles. Reinsert the SIM card, making sure it's seated correctly in the tray, and push the tray firmly back into the phone. Power it on and see if it connects.
Verify Your Carrier Account
It's worth a quick check to make sure the problem isn't on your carrier's end. An unpaid bill, an expired prepaid plan, or even a temporary network outage in your area can cause this error. Try logging into your carrier's account portal from a computer or another phone, or give their customer service a call. Confirm your line is active and in good standing.
Update Your Software
OnePlus frequently releases OxygenOS updates that include fixes for connectivity bugs, especially for a new device like the 13. Running outdated software is a common cause of network issues. Go to Settings > About device > OxygenOS version and tap on the top banner to check for updates.
If an update is available, connect to Wi-Fi and install it. I've seen early OxygenOS builds on new models have quirks that get patched out quickly. Keeping your phone updated is one of the best ways to ensure stable network performance.
Reset Your Network Settings
This step clears all your saved network configurations without deleting your personal data. It wipes your Wi-Fi passwords, Bluetooth pairings, and cellular network settings, forcing your phone to start fresh. Go to Settings > System > Reset options.
Tap on Reset Wi-Fi, mobile & Bluetooth. Confirm your choice and enter your PIN if prompted. Your phone will restart. After it boots, you'll need to reconnect to Wi-Fi and re-pair Bluetooth devices, but this often resolves persistent "not registered" errors.
Manually Select Your Network
Sometimes your phone gets stuck trying to register on a network band it can't properly access. You can manually choose your carrier to force a connection. Go to Settings > Mobile network. Tap on your SIM card name, then tap Network operators.
Turn off the "Select automatically" option. Your phone will search for available networks. When the list populates, select your specific carrier's name from the list. Wait a moment for it to register. If it fails, try the process again or switch the "Preferred network type" to 4G/3G/2G to see if it connects on a different band.
Try a Different SIM Card
This test tells you if the problem is with your SIM card or with the phone itself. Borrow a working SIM card from a friend or family member (ideally on the same carrier, but any will do for testing). Insert their SIM into your OnePlus 13.
If the borrowed SIM card connects to the network without any issues, then your original SIM is likely damaged or deactivated. You'll need to contact your carrier for a replacement. If the borrowed SIM also shows "Not registered on network," then the issue is with your phone's hardware or software.
Factory Reset Your Phone
This is your last resort before looking at hardware repair. A factory reset will erase all data on your phone, so it's absolutely critical to back up everything important first. Use Google One, or manually transfer photos and files to a computer.
Once backed up, go to Settings > System > Reset options > Erase all data (factory reset). Follow the on-screen prompts to confirm. After the reset is complete, set up your phone as new, don't restore from a backup just yet. Insert your SIM and see if the network error is gone. If the problem persists after a clean factory reset, the issue is likely a hardware fault with the phone's internal modem or antenna.
