Owners of Xiaomi and Redmi smartphones periodically encounter an annoying notification that blocks the screen when trying to make a call or send a message.The system reports that a connection malfunction or an incorrect MMI code has been entered. This error is especially relevant for Tele2 subscribers whose settings sometimes conflict with the MIUI shell. The problem can be taken by surprise when you need to urgently call or check the balance.
The problem is that the phone cannot handle correctly. USSD-request or log in after a signal fails, often due to software failures in the communication module, incorrect access point settings, or even physical incompatibility SIM-Slot cards. MMI (Man-Machine Interface is a command that connects the user to the operator’s network, and when it does not pass, the device’s functionality is blocked.
In this article, we will discuss in detail all possible causes of this malfunction on Xiaomi devices, you will learn how to diagnose the problem yourself, what settings you need to check first and when to carry the device to the service. We will consider both software methods of solving and physical manipulation of the SIM card.
The reasons for the MMI error on Xiaomi
Understanding the root of the problem is half the solution. A "misguided MMI" or "connection malfunction" error on Redmi with a Tele2 SIM card rarely occurs out of nowhere, most often due to accumulated software debris or a sharp switch between communication standards. For example, if a phone tried to switch from 4G to 3G in a bad reception zone, the communication module could "hang" in anticipation of a response from the tower.
Another common cause is the conflict between the two SIM-If one of them is set up as the main one for data and the second one for calls, the system may confuse priorities when sending. USSD-Also consider the age of the SIM card itself: old cards Tele2, The ones that were released a few years ago may not work properly with the current encryption protocols that are used by the company. MIUI.
The influence of third-party apps is not to be discounted, as various number detectors, spam blockers or Internet accelerators can intercept control of the phone's modem, at which point the attempt to dial a command like *105# is blocked by Android security, and the user sees a connection error.
- 📶 Network registration failure due to unstable signal or operator-side work.
- 📱 Conflict of settings between two active SIM-slot-card.
- 🛡️ Lockdown USSD-Requests by Third-Party Applications or Antiviruses.
- 💾 Cache of the Phone application or system services.
It's important to note that in some cases, the problem is temporary, and if you're in a subway, elevator or remote area, the phone may not have the resources to establish a secure communication channel, and in this situation, the connection problems will disappear on their own once you're in the area of reliable reception.
Basic methods of network reset and reset
The simplest and most often ignored solution is to reboot the device correctly, so you don't just turn off and turn on the screen, you have to reboot the system completely, so that the communication module can go through the initialization cycle again. To do this, press the power button and select "Switch off", wait. 10-15 Seconds, and then turn on the phone.
If a normal reboot didn't work, try switching the network mode. Go to the settings, select your own. SIM-map Tele2 And change the type of network, like switching from Preferred. 4G" Only" 3G" or "Only." 2G". This will force the phone to re-register in the operator’s network, ignoring the problem frequencies.
☑️ Checklist for quick network reset
A more radical but effective method is to completely reset your network settings, which will not delete your contacts or photos, but will return all your mobile, Wi-Fi and Bluetooth settings to factory values, and after that procedure, the phone will behave as if you just inserted a new SIM card.
⚠️ Note: After resetting your network settings, you will have to re-enter passwords from all Wi-Fi networks and re-match Bluetooth devices such as headphones or watches.
To perform the reset, go to Settings → Connection and Sharing → Reset Wi-Fi, mobile networks and Bluetooth. Press Reset button at the bottom of the screen and confirm the action. The system can request a screen unlock pin.
Configure the preferred type of network
One specific reason for Xiaomi’s MMI error is the automatic choice of network type: MIUI algorithms sometimes aggressively try to hold the 4G signal even where it is extremely weak, instead of switching to stable 3G. This leads to a connection timeout and an error in the MMI code.
To fix this, you need to manually limit the ranges. Open the settings. → SIM-maps and mobile networks. Select a SIM card. Tele2, Click on Network Type and select Preferred LTE". If the problem persists, try the "preferably" option. 3G". This is especially true in older buildings with thick walls.
There is also a hidden Android engineering menu that gives you deeper control over the radio module, and be careful when using this method, as changing the extra settings can disrupt your phone.
| Parameter | Recommended value | Description |
|---|---|---|
| Radio Band | LTE/TD-SCDMA/GSM | Standard set for Russia |
| Set Preferred Network Type | LTE only (for test) | Checking the work of only 4G |
| Ping Test | Run | Verification of server availability |
| Refresh | Click | Updating signal statistics |