Why Xiaomi shuts down the Internet during a call: a full analysis of the problem

You're on the phone, and you notice that the Internet is gone -- the pages are not loading, the messengers are hanging, and the apps are giving you a connection error -- a problem that many Xiaomi, Redmi, and POCO smartphone owners, especially on budget and mid-budget models, have, is it a firmware bug, a hardware feature, or a setting error?

In this article, we will discuss in detail all possible reasons why Xiaomi shuts down the Internet during a call – from the technical nuances of the network. 4G/5G down-to-the-box MIUI. You'll learn how to diagnose a problem on your device, which settings to check first, and what to do if standard methods don't work. FAQ Frequently answered questions and interactive survey.

Spoiler: 80 percent of the time, the problem is solved without going to the service center, but there are exceptions, and we'll talk about them.

1.Technical reasons: why the Internet is “conflicting” with calls

Before digging into the settings, it’s important to understand why the internet can shut down when a call is in or out, not by accident, but by the architecture of mobile networks and the way Qualcomm/Mediatek chipsets work.

Main technical reasons:

• 📡 Switching between 4G and 3G/2G. During the call, the smartphone is forced to “roll back” to older communication standards (if the operator does not support VoLTE), which breaks the Internet connection.
• 🔄 VoLTE and VoWiFi conflict: If both protocols are activated, the system can "mix up" which one to use, leading to a data break.
• 📱 Single-chip modem limitations: Budget chipsets (e.g. Snapdragon) 4xx Helio Gxx cannot physically handle voice traffic and high-speed internet at the same time.
• 🔋 Power saving modem. MIUI aggressively optimises battery consumption, sometimes disabling background processes, including networking.

Interestingly, on Xiaomi’s flagship models (such as the Xiaomi 13 Ultra or Redmi K60 Pro), this problem is less common due to Dual 5G support and advanced modem solutions, but owners of Redmi Note 10, POCO X3 or Redmi 9A face it regularly.

VoLTE and VoWiFi: Why their settings solve 60% of the problems

VoLTE (Voice over LTE) and VoWiFi (Voice over Wi-Fi) are technologies that allow voice traffic to be transmitted over an Internet channel without interrupting the connection to the network. If they are not configured or disabled, the smartphone will force to switch to 3G/2G when you call, which will cause the Internet to break down.

How to check and enable VoLTE/VoWiFi on Xiaomi:

1. Open the Settings. → SIM-maps and mobile networks.
2. Choose yours. SIM-map.
3. Activate VoLTE and VoWiFi switches (if they are on the menu).
4. Reboot the phone.

⚠️ Note: If there are no items in the settings VoLTE/VoWiFi, It could mean:

• 🔌 Your operator does not support these technologies (relevant to some regional providers).
• 📱 Your Xiaomi model is not compatible with VoLTE (e.g. older devices on the Snapdragon 625).
• 🔄 Firmware MIUI outdated or “curved” stitched (often after manual updating).

Check your carrier’s VoLTE support on the official website or by calling support. For example, MTS, Beeline and MegaFon have lists of compatible devices.

3. APN settings: the hidden cause of the internet shutdown

APN (Access Point Name) is the “entry point” your mobile carrier provides to the Internet. If the APN settings are set up incorrectly, the smartphone may lose connection when switching between communication standards (for example, from 4G to 3G during a call).

How to check and reset your APN settings:

1. Go to Settings. → SIM-maps and mobile networks → [Yours. SIM] → Access points (APN).
2. Click on the three dots in the top right corner and select Reset to default values.
3. If the reset didn’t work, manually create a new APN with your carrier’s settings (you can find them on the provider’s website).

⚠️ Note: If after discharge APN The internet is gone, check if the mode is activated. 2G In the network settings, also make sure that the slot is SIM-card no physical damage (e.g. bent contact).

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If you don't get the Internet after you change the APN, try to switch the phone to flight mode for 30 seconds, then turn it off. This will reset the network settings of the modem.

4. Energy saving mode and background optimization MIUI

MIUI is known for aggressive battery optimization, which sometimes strangles background processes, including network connections. If you have power saving mode on or optimized for specific applications (such as Chrome or Telegram), the Internet can be turned off when you call due to a modem shutdown.

How to disable unnecessary restrictions:

1. Go to Settings → Battery and Performance → Power Saving Mode and turn it off.
2. In Battery Optimization, find apps that need constant internet (such as instant messengers) and select them without restrictions.
3. In Settings → Applications → Application Management, check if auto-start for key services (e.g. Google Play Services) is disabled.

A critical feature of MIUI is that even if you have manually turned off the power saving mode, the system can automatically turn it on when the battery is low (below 15%).

It’s also worth checking if the Adaptive Battery feature is activated (in some versions of MIUI it’s hidden in Additional Settings → Battery), which analyzes your habits and can force the modem to “sleep” at “inconvenient” moments.

5.Firmware problems: MIUI bugs and fixing them

Sometimes the reason lies in software bugs of a particular version of MIUI. For example, in the firmware for the Redmi Note 10 Pro (MIUI 12.5) was a well-known bug, which caused the modem to “hang” when switching between 4G and 3G. In MIUI 13 on some devices VoLTE worked unstable after the update.

How to diagnose and correct:

• 🔍 Check the version. MIUI In Settings → The phone. → Version. MIUI. If it is outdated, upgrade to the latest stable version.
• 🔄 If the problem has occurred after the update, try to roll back to the previous version (via Settings). → Updating the system → Three points. → Select a Service Package).
• 🛠️ For advanced users: install custom recovery (e.g., custom recovery, TWRP) And run the clean version. MIUI Pixel Experience (if the official methods do not help).

⚠️ Note: Retracting firmware or installing a custom version may result in loss of warranty and inoperability of certain features (for example, NFC broadband 5G). Do this only if you are confident in your actions!

6. Hardware malfunctions: when without service can not do

If all software methods have been tried and the internet is still shut down when making calls, the problem may lie in the hardware:

• 📶 Damaged modem (for example, after falling or getting moisture).
• 🔌 Faulty slot SIM-cards (contacts oxidized or bent).
• 🔋 A worn-out battery that does not provide enough current for the modem during loading (call) + web-based).
• 📡 Problems with the antenna module (especially relevant after changing the screen or back cover).

How to diagnose:

1. Try inserting. SIM-If the problem persists, it is the operator's fault or SIM.
2. Check if the phone is warming up in the modem area (the top of the back cover) during the call.
3. Run the hardware test through the engineering menu (enter ##4636## and select Phone Information).

If you suspect a hardware malfunction, don’t delay a visit to the service, for example, a faulty modem can eventually completely fail, and it will cost more to replace it than early diagnosis.

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If the internet is turned off ONLY when talking on speakerphone or with connected headphones, the problem may be in the audio codec or 3.5mm connector (if any).

7.Alternative solutions: from reset to SIM replacement

If the standard methods don’t work, try these non-obvious methods:

• 🔄 Resetting network settings: Settings → System system → Resetting settings → Resetting Wi-Fi, mobile network and Bluetooth, not resetting data, but returning all network settings to factory settings.
• 📱 Replacement SIM-Old cards. SIM (Mini-SIMs in particular may not communicate well in the nano-SIM slot, causing interruptions.
• 🔌 Disabling the second slot SIM. If you use two SIM-Try to leave only one card, sometimes the modem gets confused between them.
• 🛡️ Shutdown VPN. Some of them VPN-Services conflict with VoLTE, blocking the Internet when calling.

It is also worth checking whether the function is activated Traffic Saving in the settings. SIM-It can limit Internet speeds when you're making voice calls.

If nothing works, the last chance is a factory reset (don’t forget to back up!) 90% of the time, it’s solved by networking software, but requires reconfiguration of the phone.

FAQ: Answers to Frequent Questions