Why Xiaomi is shutting down the Internet during a call – and how to fix it

You're talking on the phone, and at that point, mobile internet stops working? Xiaomi smartphones (especially Redmi models, POCO And Mi series, they often have this problem, and it can manifest itself in different ways. 4G/LTE When you call, others have a complete disconnection from the network, and others have a reboot of the Internet only after the device is restarted, and the reasons are rooted in the hardware of the phone, the settings of the operator or firmware.

In this article, we will discuss 7 main reasons why Xiaomi shuts down the Internet when calling, from simple errors in the settings of APN to conflicts with VoLTE technology. You will learn how to diagnose the problem yourself, which parameters to check first and when to contact the operator or service center. And for the models of Redmi Note 10/11/12 and POCO X3/X4, we have prepared separate recommendations – these devices are especially prone to bugs due to the features of Qualcomm Snapdragon chipsets.

Spoiler: 80 percent of the time, you can fix the problem without resetting or flashing it, but if you've tried everything, don't miss the hidden settings section of the engineering menu (#4636##) that help even when standard methods don't work.

1. VoLTE: Why Technology is to Blame for the Internet's Cliff

The most common reason is a conflict with VoLTE (Voice over). LTE). This technology allows you to transmit voice over 4G-It's a network, but it's often unstable on Xiaomi, because when you activate VoLTE, the phone can automatically switch to the phone. 3G during a call, if the operator's network does not support simultaneous voice and data transmission (so-called "Speed") SVLTE). As a result, the internet is disappearing.

How to check if VoLTE is to blame?

• 📱 Look at the network indicator in the status bar: if during the call 4G shift 3G or+ — That's the problem.
• 🔧 Go to Settings. → SIM-maps and mobile networks → [yours SIM] → Transfer of vote LTE (VoLTE) and disable the option. Then check if the Internet is saved when you call.
• 📡 Check with the operator whether your tariff supports simultaneous voice and data transmission (not all operators provide this even when VoLTE is turned on).

Important: On some Xiaomi models (e.g. Redmi 9T or POCO M3), VoLTE may be enabled by default, but it may be crooked due to outdated firmware. Update to the latest version of MIUI, which often solves the problem.

2. APN Settings Mistakes: How Wrong Parameters Break the Internet

If the Internet is only lost when you make calls, but VoLTE is turned off, then the APN (Access Point Name) settings can be to blame. Operators sometimes update these settings, but the smartphone does not automatically tighten them, and the connection crashes when you make a call.

How to check and correct:

1. Open the Settings. → SIM-maps and mobile networks → [yours SIM] → Access points (APN).
2. Click on the current profile APN and check the fields: 🔹 APN — must match the name of the operator (for example, Internet.mts.ru for MTS). 🔹 Type APN — Must default,supl or default,supl,mms. 🔹 Protocol APN — IPv4/IPv6 (if available).

Resetting to default values

Make sure that mobile data is included|Check the name. APN (must be consistent with the operator)|Delete the extra profiles APN (You should only be 1 active person)|Reboot your phone after the changes-->

⚠️ Attention: On some firmware MIUI (especially customized APN They may reset after the update. If the problem comes back, check it again.

3. Dual-band Wi-Fi Calling: Why it interferes with mobile internet

Xiaomi’s Wi-Fi Calling technology sometimes conflicts with mobile internet, and if you have this mode on, the phone may try to switch to Wi-Fi during the call, at which point the connection to the mobile network is cut off.

How to diagnose:

• 📶 See if the Wi-Fi Calling icon appears in the status bar during the call.
• 🔄 Turn off Wi-Fi and see if the problem persists. If the Internet is working when you call, it's Wi-Fi Calling that's to blame.

Decisions:

1. Turn off Wi-Fi Calling in Settings → SIM-maps and mobile networks → [yours SIM] → Wi-Fi calls.
2. If you want to leave the function, update the firmware (in new versions of MIUI 14+ bug fixed).
3. Check your router settings: sometimes IPv6 or Qos is a problem (turn them off temporarily).

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If you make frequent calls via Wi-Fi, but mobile internet is important, turn on Mobile Data Only in your settings. SIM-It'll make the phone use the cards. LTE Even with active Wi-Fi.

4. Conflict of the two SIM-Why the second one is the second one SIM "stealing

On dual-SIM models Xiaomi (for example, Redmi Note 11 Pro)+ or POCO F4) There is often a problem: when calling one SIM-The second one takes the Internet, and that's because the phone can't simultaneously support voice connectivity on one of the two. SIM and data on another.

How it works:

⚠️ Note: Some Xiaomi models with Mediatek chipset (e.g. Redmi) 10C) This bug is manifested even when you set it right, so the solution is to turn off automatic network selection in the settings. SIM-Maps and manually set the mode LTE.

5. Software bugs: when firmware or applications are to blame

If the problem occurred after the MIUI update, it was the firmware. MIUI 12.5-13 had a massive bug with an Internet cliff on calls that was only fixed in MIUI 14.

• 📲 Ad blocking apps (such as AdGuard or Blokada) that interfere with network traffic.
• 🔄 VPN-Clients (especially 1.1.1.1 or ProtonVPN) who are not properly handling network switching.
• 📡 Problematic Google Play Services Updates (solved by cache cleaning).

How to fix it:

1. Check the version of MIUI in Settings → About Phone. If it is older than 14.0.5, upgrade.
2. Run your phone in Safe Mode (press the power button → Safe Mode) If the problem has disappeared, the third-party app is to blame.
3. Clear the cache of Google Play Services: Settings → Apps → App Management → Google Play Services → Storage → Clear the cache

Hardware problems: when the modem or antenna is to blame

If none of the above methods worked, the problem may be in the hardware:

• 📡 Damaged modem (often after falls or moisture hits).
• 🔌 Oxidation of contacts SIM-cards (especially if the phone has been in high humidity conditions).
• 📶 Antenna switch malfunction (typical for Redmi 9 and POCO M2).

How to diagnose:

• Try inserting. SIM-If the problem persists, it is the operator's fault. SIM.
• Check the IMEI (type *#06#) if it is unknown or null, the modem is faulty.
• Run the network test in the engineering menu: ##4636## → Phone Information → Select SIM → View the status of "Data Service" If the status is disabled during the call - a problem in the modem.

⚠️ Warning: If the phone falls or gets wet, don't try to disassemble it yourself - contact the service.Damage damage often requires soldering, and unprofessional intervention can make the problem worse.

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If the Internet is only lost when you make calls, but the settings are correct, there's a 90 percent chance that the hardware malfunction is to blame, and then only the diagnostics at the service center will help.

7. Operator settings: why fare or network might be to blame

Sometimes the problem lies not in the phone, but in the operator’s settings:

• 📞 Your tariff does not support simultaneous voice and data transmission (even if VoLTE is enabled).
• 📡 The operator does not provide any services in your area SVLTE (simultaneous operation of the voice and 4G).
• 🔄 At the base station, technical work is carried out, because of which the phone is forced to switch to the base station. 3G.

How to check:

1. Call the operator and check if your tariff supports VoLTE and SVLTE.
2. Try manually setting the network type: → SIM-maps and mobile networks → [yours SIM] → Type of network → Select "Only" LTE" If the Internet continues to shut down, the problem is on the operator’s side.
3. Put it in. SIM-card to another phone (not Xiaomi) and check the Internet behavior when calling.

If the operator has confirmed that the problem is on his side, it remains only to wait for corrections or change the tariff, for example, MegaFon SVLTE is only available on the All for Communication and No Limit tariffs.

FAQ: Frequent questions about the problem