v2rayNG killed in the background: fixing drops after the screen locks

The classic symptom: everything works while you are using the phone, you lock it for a few minutes, come back, and the VPN icon is still in the status bar but nothing loads. Tapping reconnect fixes it instantly. That is not the node dropping out, that is Android freezing or killing the process.

Start with battery optimisation

Settings, Apps, v2rayNG, Battery, then pick Unrestricted or Allow background activity. On stock Android that is usually enough. The wording varies by vendor: Xiaomi calls it battery saver strategy, OPPO and vivo bury it under power consumption management.

Then the extra layer your vendor added

Many ROMs stack a second cleanup mechanism on top of the stock one:

• Xiaomi: long-press the v2rayNG card in Recents and lock it so a clear-all does not take it with everything else.
• Huawei: in app launch management switch v2rayNG to manual and enable all three toggles — auto-launch, secondary launch, run in background.
• Samsung: exclude it from the list of apps that get put to sleep when unused.

These paths move around between ROM versions. If you cannot find one, search the settings for battery or background.

Turn on always-on VPN

Settings, Network and internet, VPN, tap the gear next to v2rayNG and enable always-on VPN. The system will then bring the tunnel back up by itself and reconnect after drops. The same screen offers block connections without VPN; enabling it stops traffic escaping during the gap, at the cost of having no network at all while the tunnel is down.

If it still drops after all of that, then start suspecting the node — see the connection troubleshooting checklist.