When KuaiLian connects in the foreground but drops after lock screen, app switch, or sleep, contrast system battery optimization, battery-optimization whitelist, and background activity limits first—then any in-app prompt to allow background or VPN configuration. Assume the issue is OS reclaim on lock/background, not the node itself. Screen-on status flipping → reconnect loop; nothing starts after reboot → auto-connect startup. This page invents no node speeds or plan effects and does not promise “set it once, never drops.”
Someone left the phone face-down at lunch. KuaiLian showed Disconnected when they came back. The browser had worked minutes earlier; ten minutes locked killed the tunnel. They rotated countries—foreground connect worked instantly, lock screen dropped again. Moving KuaiLian from “smart restrict” to “unrestricted” in battery settings kept Connected through a half-hour lock on the same network. The difference was not which country felt “sturdier.” It was whether the OS killed the process in the background.
Screen-on Connected/Connecting flips or fixed-interval drops → reconnect loop / drops. After reboot the tray or status never starts until you open the app → auto-connect / startup. Whole-device offline after a drop, or suspected leak → Kill Switch. This page only covers lock-screen and background reclaim.
Background drop vs reconnect loop vs startup auto-connect
- Background / lock-screen drop: Foreground connect stays Connected; after lock, app switch, sleep, or leaving the app, status becomes Disconnected or needs a manual reconnect
- Reconnect loop: Even with the screen on, status flips Connected/Connecting, or drops on a fixed interval → reconnect guide (may include Wi-Fi handoffs, not only sleep)
- Startup auto-connect: After reboot the client never rises or auto-connect never runs → startup guide
Run one contrast: leave KuaiLian Connected in the foreground, lock for 3–5 minutes, unlock, and check whether status is still Connected. If it only drops after sleep and stays solid on-screen, stay here. If it flips with the screen on, leave for the reconnect article—do not mix “swap nodes” with “change battery whitelist” in one pass.
Confirm the drop is tied to lock or background reclaim
Goal: tie the drop timing to sleep / app switch—not measure node speed, and not prove a plan is “better in background.”
- After a successful foreground connect, do not swap nodes yet; note protocol and network (Wi-Fi / cellular)
- Lock or switch apps for a few minutes, then return and check status plus the system VPN icon
- In system Settings, see whether KuaiLian has battery saver, sleep freeze, background limits, or auto-cleanup (labels follow your device)
- After changing one battery/background class, retest lock on the same network
If foreground Connect never succeeds, leave this page for connection troubleshooting—do not pile battery whitelists first. When menus and the installer disagree, verify the current platform build on the download page.
Android: battery-optimization whitelist and power kills
On many OEM ROMs, foreground works until background or lock freezes the process and the VPN tunnel dies. Follow your device paths; do not memorize old brand screenshots.
1. Battery optimization / Unrestricted
In App info or Battery, set KuaiLian to Unrestricted / Don’t optimize—wording follows the current OS.
2. Background activity / autostart
Allow background run and related starts if the ROM exposes them; overlap with startup is only about keep-alive after you are already signed in.
3. Recents “lock” / exclude from cleanup
Pin KuaiLian in the recents view so a swipe-clear does not kill the VPN service.
4. Ultra / Extreme battery modes
Most VPNs stop in extreme saver—exit that mode before judging lock-screen keep-alive.
Whitelisting only lowers kill odds; it is not “guaranteed always on.” If the client shows a system dialog to disable battery optimization, follow the current prompt; copy follows the installed version.
iOS and desktop: background refresh, sleep, VPN profiles
On iOS, VPN usually depends on configuration profiles and network extensions. When lock drops the tunnel, contrast VPN still authorized, Low Power Mode, and whether the network just changed. Do not expect a node swap to “outrun” OS reclaim.
- iOS: Settings → General → VPN & Device Management / VPN—confirm the profile stays enabled; turn Low Power Mode off once for a contrast test
- Windows: Sleep, Modern Standby, and power-plan options about network while sleeping; do not force “background forever” under a saver plan
- macOS: Sleep and App Nap; confirm VPN / network extensions still allow KuaiLian
Desktop lid-close sleep cutting the tunnel is often power policy, not a dead subscription. After wake, read the client prompt before changing power options; steps may also sit in the guides hub.
In-app keep-alive and reconnect toggles
Some builds expose “keep in background,” “reconnect on disconnect,” or “always-on VPN” style switches—labels follow the current client.
- Flip one toggle at a time, then retest lock; do not stack it with battery changes in the same pass
- “Reconnect after disconnect” pulls the tunnel back up; it does not stop the OS from killing the process—battery allowance still comes first
- If after unlock it reconnects then immediately flips, move to reconnect loop instead of toggling the same switch repeatedly here
Missing menus often mean an outdated or wrong-platform installer—check the download page. Reinstall can clear local mess; it does not auto-disable OS battery saver and does not promise background forever.
Still broken: Kill Switch, reconnect loop, device limit
- Whole device offline after a drop, or suspected leak → Kill Switch—not the same layer as “power killer”
- Screen-on flips or fixed-interval reconnect → reconnect loop
- Client never starts after reboot → auto-connect startup
- Device limit or session kick prompts → device limit—battery whitelist will not fix seat caps
- No drop, only one app/site won’t open → one app/site won’t open—that is split/routing, not keep-alive
Contrasts only show whether sleep reclaimed the tunnel. They do not prove censorship resistance, streaming unlocks, or “this country node survives background better.”
Still stuck: what to record for FAQ / download
If battery and background changes still drop on lock, gather these before FAQ or in-app support:
- Platform and OS version (Android/iOS/Windows/macOS); note unusual OEM ROMs
- Whether drops happen only after lock / app switch / sleep; whether foreground on-screen stays solid
- Battery optimization, background activity, Low Power / extreme saver state (screenshots OK; mask accounts)
- KuaiLian version; exact system prompt text asking for background or VPN permission
When menus disagree with old tutorials, verify the current platform package on the download page. Install paths: guides hub.