A frozen sending indicator or an instant return of a message with a delivery error on Android most often indicates a failure in the device’s software settings or temporary instability of the network module, rather than a physical breakdown of the device.
Restoring functionality mobile communications usually does not require complex technical knowledge or contacting a service center. It is enough to sequentially check a number of parameters in the device menu, make sure that the SIM card is working correctly and, if necessary, reset the network connection configuration. Below we will analyze in detail all the diagnostic and configuration stages that will help restore the ability to exchange messages.
Before moving on to deep system settings, it is worth eliminating the most common causes of problems. Users often forget about basic things, such as having funds on their balance or choosing the right SIM card in dual-SIM devices. These simple steps allow you to solve the problem in 80% of cases without the need to interfere with system files.
Primary diagnosis and balance check
The most common reason for blocking outgoing messages is the lack of a positive balance on the mobile operator account. Even if you have an unlimited tariff for calls and the Internet, the service of sending SMS messages is often charged separately or requires a minimum amount on the account to pass authorization on the network.
Check your account status via the USSD command of your operator or in your personal account in the mobile application. If the balance is negative or equal to zero, top it up in any convenient way. After crediting the funds, it is recommended to restart the device to update registration in the cellular tower network.
It is also worth paying attention to the status of the SIM card itself. Make sure it is physically intact, has no visible damage, and fits tightly in the slot. In some cases, oxidation of contacts can lead to unstable operation of the communication module, which manifests itself precisely in problems with sending data, not voice calls.
⚠️ Attention: If the balance is positive, but messages do not go through, try sending a test SMS to your own number or to the number of another operator. This will help you understand whether your operator is blocking the service or whether the problem is localized in a specific communication direction.
Owners of smartphones with two SIM cards should check which card is selected by default for sending messages. In modern versions Android the settings may be lost after a system update, and the phone tries to send a message through a slot in which there is no active SIM card or no network coverage.
Setting up a messaging application
The standard Messages application in Android has its own settings that can block sending content. Go to the messenger settings by clicking on the three dots in the corner of the screen or the profile icon, and find the “Chat Settings” or “Advanced” section. Here it is important to check the status of the function RCS chats.
RCS technology allows you to send messages over the Internet, similar to instant messengers, but if the connection to the server is unstable, regular SMS may not be sent due to a protocol conflict. Try temporarily disabling the Chat or Enhanced Messages feature to force your phone to send classic SMS messages over the cellular network.
Another critical setting is the Message Center (SMSC). This is the technical number through which all your text messages go. If this number is lost or deleted, sending becomes impossible. Usually it is registered automatically when installing a SIM card, but sometimes manual correction is required.
Settings → Applications → Messages → Additional settings → Message CenterFind out the correct message center number from your operator (often these are short codes like +79... or international formats) and enter it in the appropriate field. After saving the changes, be sure to restart the application.
If you are using a third-party SMS application (for example, Textra or Handcent), make sure that it is set as the default application in the Android system settings, otherwise the system may block its access to the communication module.
Managing permissions and network access
The Android operating system strictly controls the access of applications to phone functions. If the Messages app was accidentally blocked from using mobile data or accessing your contacts list, it could disrupt the sending process. Check the permissions section in the general settings of your smartphone.
Go to the settings menu, find the “Applications” item and select your messenger. In the Permissions section, make sure that SMS, Phone, and, especially important for hybrid messages, Mobile Data are enabled. Without the last item, sending MMS or RCS messages will not be possible.
- 📱 Check whether the Do Not Disturb mode is enabled, which can block background data transfer.
- 📶 Make sure that the SIM card settings do not block outgoing calls and messages (the service can be activated by the operator).
- 🔋 Disable power saving mode, as it often limits the background activity of network modules.
Sometimes the problem lies in the fact that the system perceives the application as potentially dangerous. In this case, try clearing the application cache. This will not delete your conversations, but it will reset temporary files that may have become corrupted and caused a runtime error.
⚠️ Attention: Do not confuse clearing the cache with clearing data. If you click "Clear Data", your entire chat history will be permanently deleted. Use only the “Clear cache” option.
Resetting network and APN settings
If the software settings are lost at a deeper level, you may need to reset the network settings. This procedure will return all mobile communication, Wi-Fi and Bluetooth settings to the factory settings prescribed by the operator. This is an effective method of solving problems with registration on the network.
Find the “System” or “General Settings” section in your phone settings, then select “Reset settings” and click on “Reset Wi-Fi, mobile data and Bluetooth settings”. Confirm the action and wait until the communication modules reboot.
Particular attention should be paid to APN access points if the problem concerns sending multimedia messages (MMS). Incorrect access point parameters can block the transmission of data necessary for sending pictures or audio.
| Parameter | Value for MTS | Value for Beeline | Value for Megafon |
|---|---|---|---|
| Name | MTS internet | Beeline internet | Megafon internet |
| Access Point (APN) | internet.mts.ru | internet.beeline.ru | internet |
| Authentication Type | PAP or CHAP | PAP or CHAP | PAP or CHAP |
| APN Type | default,supl,mms | default,supl,mms | default,supl,mms |
To check the current APN settings, go to “Settings” → “SIM cards and mobile networks” → “Access points (APN)”. If the list is empty or the parameters differ from the official data of your operator, create a new access point manually by entering the data from the table above or taking it from the operator’s website.
☑️ Network checklist
Problems with the SIM card and equipment
The physical condition of the SIM card plays a key role in the stability of the connection. Old-style cards that have been used for many years can degrade: the chip wears out, microcracks appear, which leads to periodic network losses. In such cases, the phone may show a signal, but not allow you to send data.
Try removing the SIM card, wiping the contacts with a soft eraser or alcohol wipe, and inserting it back. Make sure the card fits snugly and does not wobble in the slot. If you have the opportunity, move the SIM card to another phone. If the problem persists on another device, the card must be replaced at the operator's salon.
It is also worth considering the compatibility of communication standards. If you are using a very old SIM card in a modern 4G/5G smartphone, there may be protocol conflicts. Telecom operators replace old cards for free with new USIMs that support all modern standards of encryption and data transfer.
What to do if the phone does not see the SIM card?
If the “No SIM card” or “Insert SIM” icon is constantly lit in the status bar, try carefully placing a small piece of paper under the SIM card (from the contacts side) to improve the pressure. If this does not help, most likely the card reader slot on the motherboard itself has failed.
The influence of third-party applications and blockers
Installed spam blocking applications, antiviruses or battery optimization apps can aggressively filter outgoing traffic. They may misclassify your message as spam or block the Messages app from accessing the network in the background.
Check the list of recently installed apps. If the problem started after installing a specific application, try uninstalling it or temporarily disabling it. In the antivirus settings, find the “Real-time Protection” or “Call Control” section and add your number or messaging application to the white list.
Sometimes conflicts arise when there are several applications for working with SMS. Android system allows you to select only one default application. If you have several of these apps installed, go to “Settings” → “Applications” → “Default Applications” and clearly indicate which application should process SMS.
⚠️ Attention: Some banking applications and security services may block sending SMS to short numbers to protect against fraud. If you cannot send a verification code to the bank, check the security settings of the banking application itself.
In rare cases, the failure may be caused by the device's memory being full. If the internal storage is full, the system cannot create the temporary files necessary to process an outgoing message. Free up at least 500 MB of free space and check the connection.
Comprehensive approach to diagnostics: start by checking the balance and rebooting, then check the application settings, and only at the end resort to resetting the network settings or replacing the SIM card.
Frequently asked questions (FAQ)
Why are messages sent only via Wi-Fi?
This means that you have the RCS (Chat) function activated or sending over the Internet, and the mobile data network is disabled or unstable. Try turning off Wi-Fi and checking whether the message is sent via the mobile data, or disable the “Chat” function in the application settings.
What does the “Not Delivered” error mean immediately after sending?
Such an error usually indicates that the message could not leave your phone or was rejected by the message center. Check the presence of a network signal, account balance and the correct message center (SMSC) number in the settings.
Is it possible to recover deleted SMS after resetting the settings?
If you did not back up your correspondence to the cloud (Google Drive) or to a memory card in advance, then after resetting the settings or clearing the application data, it is impossible to restore messages using standard means.
Why don’t you receive SMS from banks, although other messages work?
Probably, the bank number is blacklisted or in the spam blocking settings. Check your Spam folder in the Messages app and your settings to block unknown numbers. Also make sure that the “Banning SMS reception” service is not activated by your operator.
How to enable SMS sending on a dual-SIM phone?
Go to the SIM card settings and select “SMS messages”. Check the box next to the SIM card you want to use by default, or select the “Always ask” mode to select a card every time you send.