Seeing "Call Failed" or having your POCO F6 drop calls constantly is a major headache. This usually happens when your phone can't maintain a stable connection to your carrier's network. Weak signal, a software hiccup in HyperOS, or a simple setting can be the culprit.
Let's jump into the quickest fixes first, which often solve the problem in under a minute.
Toggle Airplane Mode On and Off
This is the fastest way to refresh your cellular connection. Swipe down from the top of your screen to open the Quick Settings panel. Tap the Airplane Mode icon to turn it on, wait about 10 seconds, then tap it again to turn it off. This forces your phone to reconnect to the nearest cell tower, which can clear up temporary glitches.
Check Your Signal Strength
Look at the signal bars in the top-right corner of your screen. If you only have one or two bars, you're in a weak coverage area. Move closer to a window or step outside if you're indoors. Thick walls and buildings can significantly block the signal on any phone, including the F6.
Force Restart Your POCO F6
A simple reboot can clear out minor software bugs that might be interfering with the phone app or modem. Press and hold the Power button for 15 seconds or more. Keep holding it until you see the POCO logo appear, then release. The phone will restart. This is different from a normal restart and can resolve deeper glitches.
Check for Do Not Disturb or Focus Modes
Make sure you haven't accidentally activated a mode that silences calls. Swipe down from the top and look for a moon icon or a "Silent" indicator. If you see one, tap it to turn it off. You can also go into Settings > Sound & vibration > Do Not Disturb to check the schedule and rules.
Verify Your Date and Time are Correct
Believe it or not, an incorrect system time can cause issues with network authentication. Go to Settings > Additional settings > Date & time. Make sure the "Use network-provided time" and "Use network-provided time zone" options are both turned on. This syncs your phone with your carrier's time server.
Review Your Blocked Numbers List
It's worth a quick check to ensure you haven't blocked the number you're trying to call, or that your calls aren't being blocked inadvertently. Open your Phone app, tap the three-dot menu in the top corner, and go to Settings > Blocked numbers. See if the number is listed there and remove it if it is.
Ensure Mobile Data and Roaming are Enabled
For certain call technologies like VoLTE (Voice over LTE), having mobile data enabled can help. Go to Settings > SIM cards & mobile networks. Select your SIM card and make sure "Mobile data" is turned on. If you're traveling, you might also need to enable "Data roaming" within the same menu, but be aware of potential charges from your carrier.
Update Your Carrier Services
Carrier configuration updates are pushed by your network provider to improve connectivity. These often install automatically, but you can check. Go to the Google Play Store, search for "Carrier Services," and see if an update is available. Also, check for general system updates in Settings > About phone > HyperOS version.
Switch Between 4G/5G and 3G
Sometimes, the higher-speed network bands (4G/5G) can have weaker voice call performance in certain areas. You can try forcing your phone to use 3G for calls. Go to Settings > SIM cards & mobile networks, tap your SIM, then go to Preferred network type. Try selecting "3G" or "2G/3G" and test a call. Remember to switch it back later for faster data.
Check and Reseat Your SIM Card
A loose or dirty SIM card is a classic cause of call failures. Use the SIM eject tool that came with your POCO F6 (or a small paperclip) to pop out the SIM tray. Gently remove the SIM card, wipe the gold contacts with a soft, dry cloth, and carefully reinsert it. Make sure it's seated firmly in the tray before pushing it back into the phone.
Update Your HyperOS Software
Xiaomi frequently releases updates that fix bugs, including network and calling issues. Connect to Wi-Fi, then go to Settings > About phone > HyperOS version. Tap "Check for updates." If an update is available, download and install it. I'd recommend doing this with your phone plugged into its 90W charger to ensure it doesn't run out of power during the process.
Reset Your Network Settings
This will erase all your saved Wi-Fi networks, Bluetooth pairings, and cellular settings, but it's a powerful fix for persistent network problems. Go to Settings > Additional settings > Backup & reset > Reset phone. Here, tap Reset network settings. Confirm your PIN or password, and the phone will restart. You'll need to reconnect to Wi-Fi and re-pair Bluetooth devices afterward.
Contact Your Mobile Carrier
If you've tried everything and calls are still failing, the problem might be on your carrier's end. There could be a local network outage, a problem with your account, or your SIM card might be faulty. Give their customer service a call from another phone. They can check for outages, reprovision your line, or send you a replacement SIM card.
