Short answer: Start with the least destructive checks: refresh the subscription, confirm the client imported the subscription URL, compare Wi‑Fi and mobile data, then test another current route.
1. Refresh the subscription first
A subscription profile is not just a password. It can contain current server addresses, routing rules and fallbacks. If your provider blocks an old address, refreshing the subscription is safer than deleting the client.
2. Make sure the client imported the right thing
If the profile is empty, you may have pasted a single vless:// style key or opened the link in the wrong app. Use the subscription URL or QR code from the bot and then press update inside the client.
3. Compare Wi‑Fi and mobile data
If the same profile works on Wi‑Fi and fails on mobile data, the app is usually not the root cause. Mobile operators can filter international routes differently from home internet.
4. Change one variable at a time
Do not switch DNS, server, app and routing rules in one minute. Change one thing, test one site, then write down the result.
5. Send useful support context
The best support message includes device model, OS version, client app, network type, selected route and the exact error text. Screenshots help when they do not expose private links.
When to contact support
If the profile is current and the same route fails repeatedly on one provider, contact support through the bot. Include device, OS, client app, network type, route name and time of test. Do not post private subscription links in public chats.
Fast decision tree
| First observation | Likely direction | Guide to use |
|---|---|---|
| Profile imports but server list is empty | Subscription refresh or access status | Import subscription guide |
| VPN connects but no pages load | DNS, route or default gateway | Connected but no internet |
| Wi‑Fi works, mobile data fails | Operator filtering or provider path | Wi‑Fi vs mobile data guide |
| Only one app fails | Rules, cache or service endpoints | Telegram/YouTube/Discord guide |
Why reinstalling is last
Reinstalling removes evidence: old profiles, client logs, route names and sometimes access to apps that are no longer easy to download. Refresh and compare first; reinstall only when you know what layer is broken.
Keep a known-good baseline
If one device still works, do not change it while fixing another. A working phone or laptop is a baseline: it proves the subscription and at least one route are alive. Compare the broken device against it, then adjust client, network or routing one layer at a time.
Stop after the smallest reproducible test
Keep one subscription, one client and one route while comparing Wi‑Fi and mobile data. If the failure follows the network, report the provider path. If it follows the route, try one current route and save the result.
Use the smallest safe checklist
Open Foli, refresh the subscription and test one network and one route before changing everything.