Recommended order: connect first, then route traffic
On first use, import a subscription and confirm that its configurations appear in the list. Select one as the active server, then enable the appropriate traffic-handling mode, and adjust routing last. Changing one layer at a time makes it easier to revert if something goes wrong. If you change DNS, routing, ports, and transport settings all at once, even a successful connection will not reveal which change fixed the problem.
Desktop system proxy and Android VPN mode are different ways to route traffic on different platforms. v2rayNG uses system VPN permission to create a local traffic entry point; per-app proxy can further limit which apps use it. v2rayN can use the system proxy or other traffic-handling methods as needed. Use the setting names in the guide to find the relevant features, but do not copy every toggle from one platform to the other. Check connection status, whether the app is using the proxy, and whether the remote service is reachable separately.
If only subscription updates are failing, start with troubleshooting subscription update failures. If the subscription imported successfully but websites will not load, check the active server, system proxy, and routing in turn. A single test only reflects the specific path it checks; it does not prove that every app and website is reachable.