When KuaiLian connects and browses on Wi-Fi, but turning Wi-Fi off or switching to cellular brings connect-fail, endless spinning, or an instant drop, assume the issue is on the mobile-data side: check cellular toggles and signal, dual-SIM default data, APN/access-point name, and the client’s exact prompt on cellular. Hotel/airport auth pages first → captive portal; Connected but every app/page dead → connected-no-internet; foreground fine, lock screen or background drops → background disconnect. This page invents no carrier whitelist, node speeds, or “guaranteed on data” promise.
Someone kept KuaiLian stable for half an hour on home Wi-Fi; outdoors, turning Wi-Fi off failed every time—back on Wi-Fi, it recovered immediately. Two node swaps still failed on cellular. It turned out the dual-SIM phone’s default mobile data pointed at a secondary SIM with almost no data plan: bars looked fine, data did not work. Setting default data back to the primary SIM, confirming a page loaded with Wi-Fi off, then opening KuaiLian fixed it. The difference was not a “cellular node”—it was whether cellular actually worked.
Hotel/airport Wi-Fi stuck on an auth page → captive portal. Shows Connected on any network but the whole device acts offline → connected but no internet. Drops only after lock screen, app switch, or battery limits → background disconnect. This page only covers “Wi-Fi fine; failure only on mobile data.”
Wi-Fi OK / data fails vs portal / no-internet / background
- Wi-Fi OK, mobile data fails: Same account and client work on Wi-Fi; on 4G/5G you get connect-fail, timeout, or instant drop → this page (cellular / APN / dual-SIM)
- Captive portal: Public Wi-Fi SSID is up, but hotel/airport auth is unfinished → captive-portal guide
- Connected, no internet: Status is Connected; every page/app fails on Wi-Fi or cellular → connected-no-internet guide
- Background disconnect: Stable in foreground; drops after lock/app-switch/battery saver → background-disconnect guide
Run one contrast: connect KuaiLian on Wi-Fi and confirm it works; turn Wi-Fi off, leave cellular on, open a normal page in the browser, then try KuaiLian. If cellular pages themselves fail, fix system data first; if pages load but VPN fails, read the client prompt. Don’t mix portal, full outage, and background drops in one settings pass.
Confirm the failure is cellular-only
Goal: scope the failing medium—Wi-Fi path fine, cellular path bad—not an expired account or a full outage.
- On Wi-Fi, connect KuaiLian and open a page/app; confirm the tunnel and browsing both work
- Disconnect or disable Wi-Fi; the status bar should show 4G/5G/LTE; open a normal page to confirm mobile data itself works
- Tap connect again; note the symptom: timeout, auth error, instant drop, or Connected-but-dead only on cellular
- On dual-SIM, note which SIM is “default mobile data”; switch SIMs for a contrast if needed
If cellular pages fail on the phone itself, check plan, airplane mode, or carrier suspension before stacking nodes in KuaiLian. When the installer and menus disagree, verify the current platform build on the download page.
Cellular toggles, signal, and dual-SIM default data
The most common “dies on data” cause is system-level: traffic is not on the SIM you think, or a cellular toggle/limit blocks outbound traffic.
1. Mobile data switch
Confirm Cellular / Mobile Data is on, and KuaiLian is not barred from cellular (some OSes have per-app cellular toggles).
2. Signal and airplane mode
If bars are near zero, emergency-calls-only, or airplane/battery offline modes are on, restore cellular before testing VPN.
3. Default data SIM
On dual-SIM, check “default mobile data.” A secondary SIM with no plan or a suspended line keeps Wi-Fi fine and cellular dead.
4. Roaming and travel SIMs
Abroad or after a SIM swap, data roaming off blocks both pages and VPN—go by the current system toggles.
These contrasts only show whether the cellular path works. They do not prove a carrier allows or blocks VPN, and they do not guarantee a SIM swap will connect.
APN / access-point name checks
When cellular pages are odd, or pages load but VPN handshakes always time out, check APN (access point name). Menu paths vary by OS—follow what your phone settings actually show.
- Did you edit APN: After a manual APN change, some traffic works and some does not; restore the carrier default APN and retest
- Dual-SIM, two APN sets: Only the default-data SIM’s APN applies; editing the wrong slot changes nothing
- Special / enterprise APNs: Some industry or IoT SIMs use dedicated APNs; a normal VPN handshake may fail—go by carrier and client prompts; no whitelist invented here
- Reconnect after saves: After saving APN, toggle airplane mode for a few seconds or restart cellular, then contrast KuaiLian again
Don’t paste “universal APN” lists from the web; a bad profile can kill all data. Install and setup paths: guides hub.
Drops on cellular: how to read client prompts
When cellular pages already work and only KuaiLian fails on data, trust the current client error—don’t swap a pile of nodes by gut feel.
- Timeout / no response: If the handshake never reaches the exit, contrast one protocol or node on the same cellular path—no “this protocol always works on data” claim
- Connects then drops: After ruling out lock-screen battery kills (background guide), see if the drop happens at the Wi-Fi↔cellular handoff; retest when the medium is stable
- Auth / login-style prompts: If the same account works on Wi-Fi but login fails on cellular, retry once and check system time; if it persists, see FAQ
- Connected but dead on cellular: If both media are Connected-with-no-internet, leave this page for connected-no-internet
This page lists no carrier-block catalog and promises no node that “always works on data.” Go by the current client prompt and system cellular state.
Still off: portal, no-internet, and background splits
- Actually a hotel/airport auth page → captive portal
- Connected but the whole device is offline on any network → connected but no internet
- Foreground fine; drops on lock screen or background → background disconnect
These splits only send you to the right guide. They do not prove censorship resistance, streaming unlocks, or a “better carrier for VPN.”
Still stuck: what to record for FAQ / download
If cellular toggles, dual-SIM, and APN still leave data-side failure, gather these before FAQ or in-app support:
- Whether Wi-Fi stays stable; whether cellular pages load with Wi-Fi off
- Exact symptom and client error text (screenshots OK; mask accounts)
- Single or dual SIM; which is default mobile data; whether APN was edited
- Platform, OS version, KuaiLian version; whether it only happens on roaming/abroad
When menus disagree with old tutorials, verify the current platform package on the download page. Install paths: guides hub.