A situation where incoming calls suddenly stop coming or outgoing calls on Xiaomi’s smartphone are blocked can take you by surprise at the most inopportune moment. Users often experience a subscriber hearing short beeps or a connection error message, although the signal signals show a confident signal. MIUI HyperOS or more complex network setting conflicts.
Before you carry a device to a service center, you need to conduct a thorough diagnosis yourself, eliminating the influence of external factors. Statistics show that more than 70% of such incidents are solved by simply restarting or adjusting the parameters of the SIM card.
Sometimes it's not the device itself, but the operator's actions or the physical damage to the contacts. It's important to check each item consistently to pinpoint the source of the malfunction. You shouldn't ignore even the obvious steps, because in modern devices, the software logic may not be obvious.
Basic diagnosis and verification SIM-map
The first thing to do is to make sure that the communication module is physically healthy. Often the contact between the tray and the chip is disrupted by oxidation or dust. Remove the tray with a paper clip and carefully examine the golden contacts for contaminants. Wipe them with soft lilaless fabric, avoiding the use of aggressive liquids.
If there are no visual defects, try installing the SIM card in another slot or phone to help you understand whether the problem lies in the card itself or in the Xiaomi machine. In some cases, the chip may be physically damaged or simply exhaust its life, especially if it has been in use for several years.
☑️ Verification SIM-map
Notice how the phone behaves after installing the card, if the device writes Network Search for a long time or shows an exclamation point icon, this indicates that there is no registration in the operator's network, in which case it may be necessary to replace the SIM card in the salon.
⚠️ Attention: When removing the tray SIM-Make sure your hands are dry, and getting moisture inside the case can short-circuit and cause permanent damage to the motherboard.
Network settings and operating modes
One of the most common reasons why calls to Xiaomi do not pass is the incorrect choice of network mode. Communication operators gradually turn off outdated 2G and 3G standards, transferring traffic to 4G and 5G. If the “Only 3G” or “Only 2G” mode is forcibly selected in your smartphone settings, the connection may simply not take place.
To correct the situation, go to the settings menu. → SIM-maps and mobile networks → The preferred type of network. Here you need to select the automatic mode, for example, "Preferred" 4G" or"5G/4G/3G/2G (This will allow the phone to switch between the operator's available towers independently.
Why do you need LTE only?
It's also worth checking if Flight Mode is activated. Sometimes a software failure causes the communication module to freeze off even if the antenna icon isn't displayed. Try turning that mode on and off through the notification curtain.
An important parameter is the setting of APNs, which, although they are more likely to affect mobile Internet, incorrect data can also block voice services, and if automatic settings are not applied, request them from the operator or manually enter them using data from the provider's official website.
Problems with VoLTE and HD-sound
VoLTE (Voice over LTE) technology allows high-quality voice transmission over fourth-generation networks, but not all operators and not all regions support this feature consistently. If your Xiaomi device has VoLTE enabled but the operator's network is unstable, calls may or may not be reset at all.
To check and change this setting, go to Settings → SIM-Select the SIM card you want and find the "Use VoLTE" switch. Try to change the state of the switch: if it was turned on, turn it off, and vice versa.
- 📶 Unstable. 4G: If the signal 4G weak, the phone can constantly try to support VoLTE, losing communication. 3G fix.
- 📞 Operator Conflict: Some Operators Are Blocking VoLTE on Devices Not Certified in Their Networks.
- 🔄 Update of the firmware: In new versions MIUI The VoLTE setting can be hidden or renamed to "Calls through" LTE".
There is also a hidden engineering menu where you can force activate or deactivate this feature if a standard switch is not available. To do this, dial the code # # #86583## in the Phone app. The message "VoLTE check Carrier was disabled" means that the check is disabled and the switch should appear in the settings.
Blocks, blacklists and apps
Often users block the ability to receive calls without knowing it. MIUI has a powerful anti-spam filter built in, which can mistakenly classify normal numbers as advertising or fraudulent. Check the settings of the Security app and the Antispam section.
You should also look at the Blacklist in the call settings, and it may be that an important contact or even all the unknown numbers accidentally hit it, so open the Phone app, click on three dots or a gear, and select Lock or Blacklist.
Third-party applications can also intercept call management. If you've installed any number detectors, voice recorders or conversation recording software, try temporarily removing them.
⚠️ Note: Applications for “speeding up the Internet” or “boosting up the volume” often require deep permissions and may disrupt the Android system services responsible for communication.
Resetting network settings and flashing
If the software settings are at a deep level, resetting the network will help, and this operation will not affect your personal data, photos or contacts, but will return the parameters of Wi-Fi, Bluetooth and mobile networks to factory values.
Resets can be done via Settings menu → Connection and Sharing → Reset Wi-Fi, mobile networks and Bluetooth. Once confirmed, the phone will restart and you will need to re-enter passwords from Wi-Fi networks.
In more complex cases, when even standard methods do not help, you may need a complete reset of the device (Hard Reset).Be sure to back up all important data before that, as the phone will return to the state of “shop-like”.
| Method of decision | Data retention | Efficiency | Difficulty |
|---|---|---|---|
| Reboot. | Yes. | Low. | Minimum |
| Network change | Yes. | Medium | Low. |
| Resetting network settings | Yes. | Tall. | Medium |
| Full reset (Wipe) | No. | Maximum | Tall. |
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Network resets are a safe and often effective way to resolve communication module software conflicts without losing personal files.
Hardware malfunctions of the antenna
When all software methods are exhausted and calls still don't go through, there's a high probability of physical breakdown. The antenna module in Xiaomi smartphones is a plume that connects the board to the case or individual components of the structure.
Another common problem is that the radio module itself on the motherboard fails, which can be due to a power surge, moisture ingress, or a manufacturing defect, in which case the phone may show the network, but when you try to call it, you immediately make an error or reset a call.
Diagnosing the problem at home is difficult, and if replacing the SIM card and completely resetting it did not help, it is advisable to contact an authorized service center for professional diagnosis.
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If the phone falls or falls into the water, don’t try to charge it or turn it on repeatedly.Take it to the service immediately to prevent corrosion of the antenna contacts.