Why does Wi-Fi turn off when you lock your phone—and how to fix it?

Have you noticed that your smartphone loses Wi-Fi connection after locking the screen? This issue occurs on devices running both Android, and iOS, but the causes and solutions can vary dramatically. In some cases, aggressive power-saving algorithms are to blame, while in others, firmware errors or incorrect router settings are to blame.

Users often complain that Wi-Fi disconnects 5-10 seconds after the screen turns off, and when unlocking, you have to wait for a reconnection. This is not only annoying, but also interferes with background apps: notifications stop coming, downloads are interrupted, and messengers go dormant. In this article, we'll look into this. all possible reasons - from basic settings to hidden developer options, and we will also provide step-by-step troubleshooting instructions.

Let's pay special attention to the differences between Android And iPhone: on iOS the problem is usually related to the limitations of the system, whereas Android It can be caused by dozens of factors, from firmware versions to the chipset manufacturer. We'll also consider cases where the router or ISP is at fault, not the phone itself.

1. Energy conservation is the main culprit of the problem

In 80% of cases, Wi-Fi is disconnected when blocked due to energy conservation policiesModern smartphones actively optimize battery life, and one of the first "victims" is the Wi-Fi module. Manufacturers believe that if the screen is off, the user doesn't need the internet—but this isn't always the case.

On Android Several mechanisms are responsible for this:

• 🔋 Adaptive battery (a built-in feature of Android 9+) that limits background activity of apps.
• ⚡ Power saving modes from the manufacturer (for example, MIUI Battery Saver on Xiaomi or Game Optimizer on Samsung).
• 📶 Optimizing Wi-Fi in Sleep Mode — a hidden setting that forcibly disables the module after a specified time.

On iPhone The situation is simpler: Apple does not allow users to flexibly adjust energy consumption, but sometimes background app refresh or low power mode may affect the stability of Wi-Fi. For example, if in Settings → Wi-Fi parameter disabled Connect to the network automatically, the phone may "forget" the network after sleep.

2. Wi-Fi settings in sleep mode (hidden options)

Many users don't know that Android There's a hidden option that controls how Wi-Fi behaves when blocked. It's called Wi-Fi in sleep mode and can have three meanings:

• 🔄 Always — the module remains active (maximum battery consumption).
• ⏳ Only when connected to charging - a compromise option.
• ❌ Never — Wi-Fi turns off immediately after the screen turns off.

To find this setting:

1. Go to Settings → Wi-Fi.
2. Tap the three dots (⋮) in the upper right corner and select Additionally or Advanced settings.
3. Find the item Wi-Fi in sleep mode (on some firmware versions it may be called Hibernation policy or Keep Wi-Fi on during sleep).
4. Set value Always.

Open Wi-Fi settings | Find the "More" or "Advanced" section | Select "Use Wi-Fi during sleep" | Set to "Always" -->

If this option is not in the menu, it means the manufacturer has hidden it. In this case, section for developers:

1. Activate Developer mode (Tap the build number 7 times in Settings → About phone).
2. Return to Settings → System → Developer Options.
3. Find the option Keep Wi-Fi on in sleep mode (or Wi-Fi scan throttling) and turn it on.

adb shell settings put global wifi_sleep_policy 2

3. Firmware errors and manufacturer bugs

Sometimes the problem lies not in the settings, but in software errors. For example:

• 🐞 Bugs in Wi-Fi drivers (often found on cheap smartphones with chipsets Mediatek).
• 🔄 Conflicts after update (for example, after switching to Android 13 many users Samsung Galaxy complained about Wi-Fi interruptions).
• 📱 Incompatibility with certain routers (for example, telephones Xiaomi sometimes they don't maintain connection with routers TP-Link Archer C6).

How to check if the firmware is at fault:

1. Check out reviews of your model on forums (for example, 4PDA or XDA Developers). If the problem is widespread, it will most likely be fixed in the next update.
2. Try it reset network settings (Settings → System → Reset → Reset Wi-Fi, mobile network, and Bluetooth settings).
3. If the phone supports beta firmware versions, try updating to it (but be careful - the beta may contain new bugs!).

For iPhone The following bugs are relevant:

• 🍎 Problems with iOS 16–17, when the phone "forgets" 5 GHz networks after sleep.
• 🔒 VPN Errors - If VPN is enabled, Wi-Fi may be disconnected when blocked.
• 📡 Conflicts with Mesh systems (For example, Google Nest Wi-Fi).

Solutions for iPhone:

1. Update iOS to the latest version.
2. Forget the network (Settings → Wi-Fi → ⓘ → Forget this network) and reconnect.
3. Disable the VPN or change the protocol (for example, from IKEv2 on OpenVPN).

4. Problems with the router or provider

It's not always the phone's fault. Sometimes Wi-Fi is disconnecting due to router settings:

• ⏱️ DHCP timeout — if the router distributes IP addresses for a short time, the phone may “fly out” of the network.
• 🔄 Router power saving mode (For example, Wi-Fi Schedule or Green Mode).
• 🛡️ MAC address filtering — if the phone is not on the white list, the router may disconnect.
• 📶 Unstable 5 GHz channel - Many phones have poor connection at high frequencies.

How to check:

Also worth checking:

• 🔌 Router power supply - if it is connected via an extension cord or a weak power supply, there may be voltage drops.
• 📡 Network congestion — if many devices are connected to the router, it can forcibly “reset” inactive ones.
• 🔄 Updating the router firmware — outdated software may conflict with modern smartphones.

5. Conflicts with applications and VPNs

Some programs may block background Wi-Fi activity, even if you don't notice it. Most often, the culprits are:

• 🔒 VPN clients (especially with the function Kill Switch, which breaks the connection when the VPN is interrupted).
• 🛡️ Antiviruses and firewalls (For example, Avast, Kaspersky, NetGuard).
• 🎮 Game accelerators (For example, Game Turbo on Xiaomi or GPU Turbo on Huawei).
• 📱 Battery optimizers (For example, DU Battery Saver or Greenify).

How to find the culprit:

1. Start your phone in safe mode (on Android: hold down the power button → Safe mode). If Wi-Fi is stable, one of the installed applications is to blame.
2. Disable suspicious programs one by one, checking the connection.
3. On iPhone check Settings → Privacy → Analytics & Improvements → Analytics Data — there may be logs about Wi-Fi errors.

6. Hardware malfunctions

If none of the methods helped, the problem might be iron:

• 📡 Poor Wi-Fi antenna connection (often after falls or repairs).
• 🔋 Worn out battery — when the battery is low, the phone can forcibly turn off energy-intensive modules.
• 🔥 Chipset overheating — If the phone gets hot, the system may limit Wi-Fi operation.

How to diagnose:

1. Check your phone's temperature using an app AIDA64 or CPU MonitorIf the temperature is above 50°C, it is critical.
2. Connect your phone to a charger and see if the Wi-Fi works. If so, the battery is to blame.
3. Try connecting to a different Wi-Fi network (for example, at a cafe or at a friend's place). If the problem persists, there's a problem with your phone.

Solutions:

• 🔧 If your phone is under warranty, contact a service center.
• 🔋 If the battery is at fault, replace it (cost for iPhone ~5–10 thousand rubles, for Android — 1–3 thousand rubles).
• 📱 If the problem is in the antenna, disassembly and soldering will be required (price depends on the model).

7. Specific cases: Mesh systems, corporate networks, public points

In some scenarios, Wi-Fi may be disconnected due to network features:

• 🏢 Corporate networks With 802.1X (EAP) - require re-authentication after sleep.
• 🌐 Public Wi-Fi (at airports, hotels) - often have a session time limit.
• 📡 Mesh systems (For example, Google Nest Wi-Fi or TP-Link Deco) - can "throw" the phone between nodes, which leads to a break.
• 🔒 Network with Captive Portal (where you need to enter your login/password in the browser) - the phone cannot automatically repeat authorization.

Solutions:

• For corporate networks: ask the administrator to increase the session timeout or configure EAP-SIM (if supported).
• For public Wi-Fi: Disable automatic connection to this network.
• For Mesh systems: disable in the router settings Fast Roaming (802.11r) or tether the phone to one node.
• For Captive Portal: Use apps like WiFi Captive Login for automatic authorization.

FAQ: Frequently Asked Questions