VPN not working or not connecting: 15 causes and how to fix them

The VPN is on but there is no internet. Or the Connect button spins forever. Or everything works but video takes a minute to load. Below are 15 common causes and what to do about each. Go from top to bottom: the first items fix most problems in a minute.

Quick diagnosis first

Answer three questions to know where to look:

1. Does the internet work without the VPN? Turn the VPN off and open any site. If that fails too, the problem is the network, not the VPN.
2. Does the VPN work on another network? Switch from Wi-Fi to mobile data or vice versa. If it works on one and not the other, it is the provider.
3. Does it work on another device? If the phone is fine and the laptop is not, it is that device’s settings.

The VPN will not connect

1. Outdated subscription

The most common cause. The service may have changed a server address or settings, and the app remembers the old ones. Fix: refresh the subscription. In Happ — the refresh button or pull down on the server list. Then reconnect.

2. The server is unreachable from your provider

A specific address may stop responding on a particular carrier. Fix: pick a different server from the list manually.

3. Your subscription expired

Fix: check the expiry date on the key page (“My key” on the site). With Klen VPN, renewing with the same contact adds days to the same key — no need to reconfigure the app.

4. Device limit exceeded

If the key is used on more devices than the plan allows, new connections may fail. Fix: disconnect devices you are not using. Klen VPN allows 5 devices, and support can reset linked devices if needed.

5. Wrong time on the device

Encryption is sensitive to clocks: if your time is several minutes off, a secure connection may not be established. Fix: turn on automatic date and time.

6. Another VPN, proxy or antivirus interferes

Two VPNs at once conflict. Some antivirus suites and “internet boosters” intercept traffic. Fix: turn off other VPN apps, work profiles and system proxies, and temporarily disable your antivirus web shield.

7. Missing VPN permission

On iPhone and Android the app needs system permission to create a VPN configuration; on a computer, admin rights for TUN mode. Fix: delete the configuration in VPN settings and reconnect, allowing the system prompt.

Connected, but sites do not load

8. DNS problems

The tunnel is up but site names do not resolve. Fix: reconnect; on a computer switch the client to TUN mode; check that no DNS server is hard-coded in your network settings.

9. Mobile internet whitelists

Since September 2025, during mobile internet restrictions in some Russian regions only sites from an approved list work — banks, government services, marketplaces, large Russian services. In this mode no VPN works: the connection to the VPN server is simply not allowed.

How to tell: on mobile data only government services, your bank, VK and marketplaces open, and nothing else does — with or without a VPN. Fix: connect to Wi-Fi or wait for restrictions to lift. Home internet and Wi-Fi are not affected by whitelists.

10. The protocol is filtered by your provider

Carriers filter known VPN protocols. Legacy ones — OpenVPN, L2TP, PPTP — are blocked most often. Since late 2025 there have also been attempts to restrict VLESS by indirect signs, differently on different carriers. Fix: refresh the subscription (the service may have issued new settings), try another server, and email support with your carrier and city — that helps find a fix quickly. More in VLESS and Reality explained.

11. A specific site blocks VPNs

Some sites — banks, streaming services, government portals — reject visitors from data-center or foreign IPs. Fix: open that site without the VPN or set up split tunneling so that app bypasses the VPN.

The VPN is slow

12. The internet itself is slow

A VPN cannot be faster than the line underneath it. Fix: run speedtest.net without the VPN. If it is slow without it, the network is the problem.

13. A distant or busy server

Fix: choose the nearest server. From Russia and Northern Europe, Finland, Estonia and the Netherlands are fastest. If there is only one server, reconnecting sometimes changes the route.

14. Weak Wi-Fi or a crowded network

In cafés and hotels dozens of people share one connection. Fix: move closer to the router, switch to 5 GHz or to mobile data.

15. Battery saving and background limits

On Android skins (MIUI, HyperOS, One UI, EMUI) the system may put the VPN app to sleep, so the connection drops and reconnects. Fix: remove battery restrictions for the VPN app and enable Always-on VPN. Details in VPN on Android.

Device-specific issues

When to contact support

If you have gone through the list and the VPN still does not work, contact support — the problem will be found faster. Include:

• device and OS version;
• the app (Happ, v2RayTun, etc.);
• your provider or carrier and city;
• what exactly happens: will not connect, connects without internet, slow;
• whether it works on another network.

Klen VPN support: klenvpn@outlook.com. If you still cannot connect, we refund your payment within 7 days.

Summary

• Start by refreshing the subscription and changing the server — that fixes most problems.
• Check whether the internet works without the VPN and on another network.
• If only banks and government sites work on mobile data, it is a whitelist — no VPN works in that mode.
• Slow? Choose the nearest server and test your speed without the VPN.