I can’t block the number on the Xiaomi phone: fixing errors

The situation where intrusive calls from spammers or former partners continue to flow despite attempts to add them to the blacklist, causes irritation to any smartphone owner. Owners of Xiaomi, Redmi and Poco devices often find that standard locking methods that worked on other Android devices fail here or require non-obvious actions. MIUI HyperOS with Google system services and features SIM-map.

Understanding why the system ignores your commands requires analyzing several factors, from the security app’s access rights to the operator’s specifics. Often users simply don’t notice that the addition of a contact has occurred, but the call filtering settings have remained in the default state. In this article, we’ll take a detailed look at each step you need to take to regain control of incoming traffic.

Sometimes the reason for the inability to block is a simple software failure or a conflict of firmware versions. If you upgrade to the latest version of Android, the old settings may stop working correctly. It is important not to panic, but to consistently check the settings, because in 90% of cases the problem is solved inside the menu of the phone without contacting the service.

Verification of access rights and operation of the application Security

Unlike pure Android, where locking functions are often built into the “call caller”, the Xiaomi ecosystem has brought call management to a separate system application Security. This component is responsible for filtering spam and blocking unwanted subscribers. If the application does not have the necessary permissions or its operation is limited by the power saving system, adding a number to the blacklist will only happen visually, but in reality calls will continue to arrive.

You need to make sure that the application is allowed to run in the background. MIUI aggressively kills background processes to save charge, which can interrupt the call filter. Go to the application settings and force it to remain active so that the lock works even when the screen is off.

It's also worth checking if the number itself is set as an exception, and sometimes users accidentally add a contact to a "White List" that takes precedence over a blacklist, in which case no call bans will apply as long as the contact is on the "Trusted List."

• 📱 Open the Security app and go to the Antispam section».
• 🔒 Click on the settings gear and make sure the Lock switch is active.
• 📞 Check the Black List tab for the number and status you need.
• ⚙️ In the “Permissions” section for the Phone and Security app, enable access to contacts and call logs.

⚠️ Note: If you use a third-party caller (e.g. from Google or Truecaller), the built-in blacklist of Xiaomi may not work.

Locking settings through the standard interface

The standard action algorithm often misses important nuances. When you open the call log and click on a number, the menu may offer the "Block" option, but it doesn't always add a number to the deep system filter. For guaranteed results, you'd better use an extended control menu. Go to the Phone app, click three dots in the corner and select Settings, and then Lock.

It's important to set the rules right here, and it allows you to block not just specific numbers, but entire categories, like Hidden Numbers or Unknown Numbers, and if you're having a problem with mass spam, it makes sense to activate these global filters that users often ignore.

If you have multiple Xiaomi devices, enable blacklist sync via Mi Cloud, which will lock the number on one device and will automatically be banned on a tablet or second phone if they are tied to the same account.

Operator code use and network restrictions

Sometimes the phone is technically functional, but the locking doesn't happen because of carrier-side restrictions. In some regions or tariff plans, number detection services (AON) work specifically. If the caller hides his number, standard locking by numbers may not work, because the phone simply does not receive the caller's digital ID.

For these cases, there are carrier service codes that allow you to connect the Anti-Definition service or the Blacklist service at the network level, which means that the call will be cut off even before it reaches your Redmi or Poco smartphone, and the codes may vary depending on the region and the provider.

Below is a table of codes for managing forwarding and locking, which can help in difficult cases when software methods are powerless, but remember that activation of network services can be paid.

Third-party applications and software conflicts

If Xiaomi’s built-in tools fail, users often turn to third-party solutions from Google Play, such as Truecaller, Getcontact or Calls Blacklist. However, there is another potential cause of the problem: application conflict. Android does not allow two programs to manage the call log at the same time. If you installed a new blocker but did not disable the old one, the system can “bewilder” and fail to execute the lock command.

With third-party software, you need to give it maximum rights. Modern versions of Android (11, 12, 13, 14) require you to manually allow the app to be the default app for working with Caller ID and spam. Without this permission, the app will see calls, but will not be able to interrupt them.

Also, be aware that some cleaners and antiviruses may block applications to filter calls, considering them suspicious. If you use comprehensive optimization solutions, add your blocker to the exceptions.

• 📲 Remove all unnecessary apps to block, leaving one main one.
• 🛡️ In the Special Options settings, check if access rights conflict.
• 🔄 Update the spam database in the blocker app via Wi-Fi.
• 🚫 Turn off “Smart Lock” in the settings MIUI, if you use third-party software.

⚠️ Note: When you install third-party number detectors, you transfer your contact database to the developer servers, which can lead to the leakage of personal data of your acquaintances.

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Expert advice: For maximum efficiency, use the bundle: a built-in blacklist of MIUI for specific numbers + a third-party application (like Truecaller) with disabled contact synchronization for the spam database.

Specifics of the work in the mode “Do not disturb”

Users often confuse the locking of a number with the Do Not Disturb mode. If this mode is activated, the phone may not ring at all, or vice versa, skip calls from favorites, ignoring other settings, check whether this mode is activated accidentally on a schedule or manually.

There are subtle exception settings in Do Not Disturb mode, such as a re-calling checkbox that misses a call if the same number calls twice within 3 minutes, often perceived as a lock failure, when it is actually a regular emergency feature.

And then HyperOS and newer versions of MIUI have a Silence of the Unknown feature that sends all calls from numbers that aren't in your phone book straight to voicemail, or just jamming a call without notice, which can be a radical but effective solution.

Network reset and system errors

If none of the software methods worked, there may have been a build-up of errors in network configuration files. Network resets won't delete your personal files or contacts, but will return to factory settings for Wi-Fi, Bluetooth and mobile data. This often helps if the lock stops working after the firmware update.

To perform the reset, go to Settings → Connection and Sharing → Reset Wi-Fi, mobile networks and Bluetooth. After restarting the phone, check the lock. If that didn't work, the problem may lie in damage to the system cache of the Phone application.

Try clearing the cache and data of the Phone and Contacts app. Go to Settings → Apps → All apps, find Phone and select Clear. Be careful: Clearing the data can delete your call history, but not your contacts if they are synchronized with your account.

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In 80% of cases, the problem is solved by checking the access rights of the Security application or disabling conflicting third-party calls.

Frequently Asked Questions (FAQ)