When a smartphone suddenly loses its network, it can be taken by surprise at the most inopportune moment. If your Xiaomi stopped seeing the SIM card, it does not always mean a critical failure of the device or the failure of the communication chip itself. Often the problem lies in the software failure of the MIUI operating system or banal oxidation of contacts, which is easy to fix yourself.
Owners of Redmi and Poco devices experience similar incidents with enviable regularity, especially after updating the firmware or mechanically impacting the gadget. It is important not to panic and consistently check all possible points of failure, from the physical condition of the tray to deep network settings.
In this article, we will discuss all the effective methods of restoring communication that will help bring your phone back to life without visiting the service center, you will learn how to correctly diagnose the problem, what hidden settings can block the module and when it is really time to change the SIM card.
Primary Diagnosis and Physical Causes
Elementary physical factors must be ruled out before you get into the wilds of software settings. Mechanical displacement of a SIM card in a tray is the most common cause of a sudden disappearance of the network, especially if the phone has recently fallen or been vibrated.
Remove the tray with a special paperclip and carefully examine the golden contacts on the card itself and inside the phone slot. Even microscopic dust or fat spots from the fingers can disrupt electrical contact, which will make the system assume that the SIM card is missing.
⚠️ Warning: Never use metal objects (needles, pins) instead of a paper clip to extract the tray, as it can accidentally close contacts and damage the motherboard of the device.
Gently wipe the chip with a soft dry cloth or eraser, then blow the slot in the phone.Make sure the card is mounted on the correct side and sits tightly in the tray frame without dangling with a slight shake.
- 📱 Check the integrity of the plastic base of the SIM card for cracks or chips.
- 🧹 Clean the contacts with a wipe or alcohol wipe to remove oxides.
- 🔄 Try installing the SIM card in the second slot if it is free.
- 📏 Make sure the tray is fully recessed into the body and does not protrude outwards.
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If you have an old SIM card that is cut out of a larger format by hand, it may have uneven edges, in which case it is better to ask the operator for a new card with a number saved, since micro-shifting of such a "homemade" often leads to loss of contact.
Software resetting of network settings
If physical manipulations fail, the problem is likely software, and the Android operating system may have incorrectly updated modem drivers or misconfigured preferred networks.
The safest way to fix this is to reset your network settings, which won't delete your personal files, photos or apps, but will return all your connection settings to factory values, and you'll have to re-enter your Wi-Fi passwords and your Bluetooth device.
To do this, go to Settings → Connection and Sharing → Reset Wi-Fi, mobile networks and Bluetooth. Confirm the action and wait for the interface to restart. After that, the phone will re-register on the operator’s network.
☑️ Checklist before network reset
Often, after this procedure, the login errors disappear on the network, and the IMEI of the device begins to be correctly determined by the base stations.
Verification of work SIM-maps in other devices
To fully understand where the root of evil lies, in the phone or in the SIM card itself, cross-testing is needed, a key diagnostic step that separates Xiaomi’s software glitch from the operator’s physical chip malfunction.
Put your SIM card in any other smartphone or even a button phone, and if the network loss problem is repeated on another device, it's not your Redmi, so you need to contact the carrier's office to change the SIM card.
The reverse situation, when your SIM card works perfectly in someone else’s phone, and your Xiaomi constantly disappears, indicates a problem with the communication module or tray of a particular device, and it can also be a sign of frequency incompatibility or an outdated version of the firmware.
| Symptoms | On another phone. | Probable cause | Decision |
|---|---|---|---|
| No network, says "No SIM." | It's stable. | Faulty tray or module Xiaomi | Repair or replacement of the tray |
| Permanent communication breakdowns | It's stable. | MIUI Program Conflict | Resetting or flashing |
| Phone doesn't see the map | He can't see either. | SIM burned or damaged | Replacement at operator |
| Emergency calls only. | It's stable. | Blocking IMEI or network | Checking the status of the operator |
Configure the preferred type of network
Modern Xiaomi smartphones support many communication standards, from 2G to 5G. Sometimes automatic choice of mode of operation leads to the fact that the phone tries to “catch” a 4G or 5G signal where its coverage is unstable, which is why communication with the base station is constantly lost.
Try force-switching the network type. Go to Settings. → SIM-maps and mobile networks → Select a SIM card. → The preferred type of network, if you have"5G preferably, change to"4G This often stabilizes the connection in areas of uncertain reception.
It’s also worth checking if the 4G Only option is enabled if you’re in an area where fourth-generation coverage is intermittent.Switching to 3G/2G mode can temporarily save the situation if you need to make an urgent call, although Internet speeds will be slow.
⚠️ Attention: Forced incorporation of the “Only” regime 4G" through an engineering menu can result in you being left without communication at all if there is no coverage in your area LTE. Use this function with caution.
In some cases, it helps to turn on and off flight mode, which causes the modem to completely reboot and re-enter the network, which is more effective than simply waiting for a signal.
Resetting APN settings and working with the operator
APNs are responsible for connecting to the Internet and the carrier’s multimedia services correctly, and if that data is corrupted or altered by a third-party application, the phone can formally see the network but not transmit data, creating the illusion of a non-working SIM card.
In the mobile network settings menu, find the "APN" option. Click on the menu (three dots in the corner) and select "Reset settings." This will return the original settings for your carrier that were downloaded when you first installed the SIM card.
If the reset didn’t work, create a new hotspot manually by taking up-to-date data from your mobile operator’s official website. Pay attention to the username and password fields – sometimes they must be filled in, even if they seem optional.
- 🌐 Make sure that in the settings APN The correct protocol is chosen (IPv4/IPv6).
- 📵 Check if the background traffic limit is worth it for system services.
- 💳 Make sure that the account has funds and the tariff has not expired.
- 📞 Call the operator to make sure there is no technical work on the towers.
Secret code for checking IMEI
Radical measures: resetting and reflashing
When all of the above methods are exhausted, the final software frontier is a complete data reset (Hard Reset), which will remove all information from the phone, returning it to the “out of the box” state, so be sure to back up important data in advance.
A complete reset removes all system errors, conflicting caches, and incorrect configurations that may have accumulated during use, often after this procedure, the "glue" communication module begins to work as a new one.
Even if a full reset didn't work, and the SIM card keeps disappearing, there's a high probability of hardware failure, which could be a retiring antenna plume, a microcrack on the board, or the radio module itself fails, in which case self-repair without soldering equipment and skills is impossible, and you need to contact the service.
⚠️ Before handing over the phone for repair, be sure to remove the SIM card and memory card, so as not to lose access to accounts and personal files.
Don't delay the diagnosis, because the constant surges in voltage when trying to log in to the network can finally finish off the communication module, it is better to solve the problem early, before it requires a replacement motherboard.