If your POCO F6 suddenly says "No SIM card" or "Emergency calls only," you can't make calls or use mobile data. This is usually a quick fix, often just a loose card or a software hiccup. Let's get your connection back.
I'd start with the simplest fix first. Turn your phone off completely using the power button, then use the SIM ejector tool to pop out the tray. Take out the SIM card, give the gold contacts a gentle wipe with a clean, dry cloth, and carefully reseat it. Make sure it's clicked into the tray properly before sliding it back in. Power the phone on and see if it recognizes the SIM.
Perform a Force Restart
If the SIM is seated correctly but still not detected, a force restart can clear temporary system glitches. On the POCO F6, you press and hold the Power button for about 15 seconds. Keep holding it until you see the POCO or HyperOS logo appear on the screen, then you can let go.
This is different from a normal restart and often fixes odd software behavior without deleting any of your data.
Check Your SIM Card Status in Settings
Sometimes the SIM gets disabled in software. Swipe down from the top of your screen twice to open the full Quick Settings panel, and make sure the Airplane Mode icon isn't active. If it is, tap it to turn it off.
Next, go into Settings > Mobile network. You should see your SIM listed here. Tap on it and ensure the toggle at the top for that SIM card is switched on. If you have two SIMs installed, check the status for both slots.
Test the SIM Card in Another Phone
This is the best way to figure out if the problem is with your POCO F6 or the SIM card itself. Power off another phone, insert your POCO F6's SIM card, and turn it on.
If the other phone also fails to detect the SIM, the card itself is likely faulty or deactivated. You'll need to contact your carrier for a replacement. If the SIM works perfectly in the other device, then the issue is with your phone.
Clean the SIM Card and Tray Thoroughly
Dust or pocket lint in the SIM tray can block the contacts. Power off your phone and remove the tray again. Use a can of compressed air to blow out any debris from the tray and the phone's slot.
Inspect the SIM card's gold contacts for any scratches, discoloration, or dirt. You can clean them gently with a cotton swab dipped in a tiny amount of isopropyl alcohol. Let it dry completely for a minute before reinserting.
Update Your Phone's Software
Software bugs in HyperOS can sometimes cause connectivity issues. Xiaomi releases updates that often include fixes for these kinds of problems. To check, go to Settings > About phone > HyperOS version.
Tap on "Check for updates." If an update is available, it's a good idea to install it. Make sure your phone is connected to Wi-Fi and has at least a 50% charge, as the 90W charger can top it up quickly if needed.
Reset Your Network Settings
This will erase all your saved Wi-Fi networks, Bluetooth pairings, and mobile network configurations, but it won't touch your personal photos or apps. It's a strong fix for persistent network issues.
On your POCO F6, navigate to Settings > Additional settings > Back up and reset. Tap on "Reset phone" and then select "Reset network settings." Confirm the action and your phone will reboot. Afterward, you'll need to reconnect to Wi-Fi and re-pair Bluetooth devices.
Configure the Access Point Name (APN)
Incorrect APN settings will stop mobile data from working and can sometimes interfere with basic network registration. Go to Settings > Mobile network > select your SIM > Access Point Names (APN).
Tap the plus (+) icon at the top to add a new APN. You'll need to get the exact settings (like APN, MMSC, MMS proxy) from your carrier's website or customer support. Enter them carefully, save the new APN profile, and then select it to make it active.
Try Manual Network Selection
Your phone usually finds and connects to your carrier's network automatically. If that process is glitching, you can do it manually. Go to Settings > Mobile network > Network operators.
Turn off the "Choose automatically" toggle. Your phone will search for available networks. When the list appears, select your carrier's name from it. This can force a fresh, stable connection.
Check for Physical Damage and Consider a Factory Reset
Look closely at the SIM tray. Is it bent, cracked, or does it feel loose when you insert it? A damaged tray won't hold the SIM card at the correct angle for the contacts to connect. This would require a repair.
If all else fails and you're certain the SIM card works in other phones, a software corruption might be the cause. A factory reset is your last resort. Before you do this, ensure everything is backed up. Go to Settings > Additional settings > Back up and reset > Erase all data (factory reset).
