Why Xiaomi does not send SMS: a complete guide to troubleshooting

When a message freezes in “Send” status or returns instantly with a red exclamation point, it can be taken by surprise at the most inopportune moment. For owners of Xiaomi, Redmi and POCO smartphones, this problem is especially urgent, given the aggressive optimization of MIUI and HyperOS, which often blocks background processes. Users are faced with the fact that incoming messages come in correctly, and outgoing ones are blocked for no apparent reason, which causes confusion and loss of important information.

The main challenge lies in the multi-layered protection system that the manufacturer implements. Antivirus algorithms can mistaken standard SMS for spam or potential threat, especially if there are links or specific codes in the text. In addition, malfunctions in virtual carriers such as Mi Message, or conflicts with new versions of Android create additional obstacles to normal communication. In this article, we will discuss all possible causes and propose working methods for eliminating them.

Diagnostics of the problem: why is sending blocked

Before we take any drastic action, we need to understand the nature of the error. Most often, the problem is not the hardware of the phone, but software conflicts or incorrect network settings. Android on Xiaomi devices is closely integrated with Google services, and desynchronizing time or date can instantly disrupt the protocol of data transmission over the cellular network.

One common cause is overflowing memory from the standard Messages app. Cache files that accumulate for months can cause crashes in the sending engine. It is also worth considering that some carrier plans have limits on the number of messages sent per day, and blocking can come directly from the provider, not from the device.

It is important to pay attention to the format of the message. If you are trying to send multimedia content (MMS) or long text that is broken into several parts, you may need special settings of the APN access point. Without the correct Internet parameters, such data is impossible to transmit, even if normal mobile traffic is stable.

Checking network settings and SIM-map

The first step in troubleshooting should be to check the physical condition. SIM-Sometimes the contact in the tray is oxidized, or the card itself is damaged, which causes periodic loss of signal. Try to remove the SIM card, wipe the contacts with soft cloth and put it back, making sure that the tight fixation is tight.

In the settings of the smartphone, you need to check whether the correct type of network is selected. 4G/LTE and 3G It helps to reconnect to the operator's messaging center, and it's also worth making sure that the system doesn't activate Do Not Disturb or Airplane mode, which can block data transmission.

Special attention should be paid to the paragraph “Centre of communications» (SMSC). This is the technical number that all your text messages go through. SIM-The card is the wrong number or the field is empty, it will not be possible to send it. Usually this number is pulled up automatically, but if it fails, you need to manually write it out, finding out the current value on your operator's website.

⚠️ Note: If you use two of these SIM-card, make sure that the SMS application selects the card from which you plan to send.The system may by default try to send a message from the card on which you ran out of money or no coverage.

Setting up an APN access point for MMS and SMS

Multimedia messages and some types of text notifications require proper configuration of the APN (Access Point Name) access point, which is unique for each operator (MTS, Beeline, MegaFon, Tele2, etc.) and region. Errors in this section often lead to the message spinning indefinitely.

To check or change settings, go to the Settings menu. → SIM-maps and mobile networks → Choose. SIM-map → Names of access points (APN). Your operator profile should be active here, and if the settings are lost, they can be restored automatically or manually by taking data from the provider's official website.

After making the changes, be sure to restart the device. If the problem persisted in the wrong parameters of access to the operator's gateway, after the restart, the system will apply new configurations, and the sending should resume.

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Sometimes the easiest way to remove an existing APN profile is to click the Reset to Default Settings button (or Menu → Reset) so that the phone downloads the current settings from the network itself.

Working with the Messages app and cache

Google's standard Messages app or MIUI system app accumulates a huge amount of temporary files over time, which speeds up work, but when the database is damaged, it can block all functionality. Cache cleaning is a safe procedure that will not delete your correspondence, but will eliminate software errors.

To do the cleaning, go to Settings → Applications → All Applications → Messages. From the menu that opens, select Memory and click Clear Cache. If the problem is more serious, you can try to click Clear All, but first make sure important dialogs are saved or synchronized.

It's also worth checking the app's permissions. HyperOS can restrict background activity. Make sure the app has rights to:

• 📱 Access to contacts and phone book.
• 🌐 Access to mobile internet and Wi-Fi.
• 🔔 Displaying notifications and working in the background.
• 📍 Geolocation (required for some spam detection functions).

If the cleanup didn’t work, try updating the app through the Google Play store.Developers regularly release patches that fix compatibility bugs with new versions of Android.In some cases, switching temporarily to an alternative client, such as Textra or Pulse SMS, helps to check if the problem is in a particular software.

The Impact of Mi Message and Antivirus

A unique feature of the Xiaomi ecosystem is the Mi Message feature, which allows you to send messages to other Xiaomi users for free over the Internet. However, this service often conflicts with standard SMS sending, especially if the Internet connection is unstable.

You can turn this off if you don't use it all the time, and you can do this in the Messages settings, find Mi Message and turn the switch to off, which will force the phone to use only the carrier's standard communication channels, which often solves the problem of getting stuck.

Built-in antivirus and spam protection also play an important role: Aggressive filters can flag short codes from banks or delivery services as dangerous and block them from being sent or received. Check the Blacklist in the security settings and make sure that important numbers are not included.

Network resets and radical measures

If none of the software methods worked, there may be deep network protocol configuration errors in the system, in which case the effective solution is to reset the network settings, which will return the Wi-Fi, Bluetooth and mobile settings to factory values, but will not affect your personal files, photos or contacts.

You can reset via the Settings menu → Connection and Sharing → Reset Wi-Fi, mobile networks and Bluetooth. Once confirmed, the phone will reboot. You will need to re-enter passwords from Wi-Fi networks and set up Bluetooth headsets, but this often “cures” even the strangest network glitch.

⚠️ Note: Before resetting your network settings, make sure you remember passwords from your Wi-Fi networks, as they will be deleted from the device’s memory.

As a last resort, if the problem is only observed after a firmware update, consider rolling back on the previous version or waiting for a patch from the manufacturer. Sometimes bugs in new versions of MIUI are massive and are only fixed centrally.

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Network resets are a safe and often the only way to fix communication protocol software conflicts that are not solved by a simple reboot.

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