Almost every VPN problem falls into one of three buckets: it won't connect at all, it connects and then drops, or it connects but nothing about your traffic actually changes. Each bucket has its own short list of usual causes, and telling them apart is most of the fix.
"My VPN isn't working" covers three completely different failures, and the fix for one does nothing for the other two. A guide that starts with "try reinstalling it" is guessing at which one you have instead of asking.
This page starts with the question instead: which of the three is actually happening, then works through the specific causes and fixes for that one, plus the error codes and the firewall issues that show up across all three.
Why Won't My VPN Connect at All?
This is the bucket where the app never reaches "connected" in the first place. The usual causes, in order of likelihood: the wrong username or password, a server that's temporarily down or overloaded, or a port the app needs being blocked somewhere between you and the server - your own firewall, your router, or your network operator's.
Three different failures, three different fixes - which box matches yours decides where to look first.
| Symptom | Likely Cause | First Fix |
|---|---|---|
| Never connects | Wrong credentials or server | Re-enter details, try another server |
| Drops every few minutes | Battery optimization | Exclude the app from power saving |
| IP address unchanged | Split tunneling or a DNS leak | Check with IP Lookup, disable split tunneling |
| "Authentication failed" | Expired password or subscription | Re-enter credentials by hand |
| Very slow speeds | Distant or overloaded server | Switch to a nearer server |
| Works on Wi-Fi, not mobile data | Carrier blocking VPN ports | Try a different protocol |
| Error code in the 800s | Blocked port on a firewall or router | Check the firewall, open the required port |
| Connects, then the app crashes | Outdated app version | Update or reinstall the app |
Before anything else: confirm the server address and password are current, since both expire or get reissued more often than people check. Then try a different server on the same provider - if that one connects, the first server was the problem, not your setup.
Why Does My VPN Keep Disconnecting?
This is a different failure from not connecting - the tunnel establishes fine and then drops minutes or hours later. Phones and laptops both have power-saving features that pause background network activity to save battery, and a VPN app is exactly the kind of background process they target first - Android's own Doze and App Standby documentation describes exactly this behavior. Switching Wi-Fi networks, the device going to sleep, and a weak signal all interrupt the tunnel the same way a dropped call interrupts a conversation.
- Exclude the VPN app from battery optimization in your device's battery settings, so the system doesn't pause it to save power.
- Turn on the kill switch if the app has one - it won't stop the disconnects, but it stops your real traffic from leaking out during the gap.
- Try a different protocol if the app offers a choice - some hold up better than others on unstable or mobile connections.
Why Is My VPN Connected But My IP Hasn't Changed?
The app says connected, but a lookup still shows your own address. This is its own dedicated failure with its own set of causes - a split-tunneling setting excluding your browser, a DNS leak sending lookups outside the tunnel, or a stale cached result - why is my VPN not changing my location covers each of those in full rather than repeating it here.
What Does "Authentication Failed" Actually Mean?
Exactly what it says - the server rejected the username or password you sent, which is different from every other error on this page in that it's rarely a network problem. The usual causes are a password that was reset or expired, a subscription that lapsed, or a username typed with the wrong case or an extra space carried over from copy-pasting. Re-entering the credentials by hand, rather than pasting them, catches more of these than people expect.
Why Is My VPN So Slow It's Unusable?
Encryption and an extra hop through a server both add some delay, so a VPN being somewhat slower than a direct connection is normal. Unusably slow points at something specific: a server that's overloaded or physically far away, a protocol that trades speed for extra security, or your own connection being the actual bottleneck and the VPN just making an already-slow line more noticeable. Switching to a nearer server is the fastest thing to try first.
Could Your Firewall or Antivirus Be Blocking It?
Security software is designed to be suspicious of exactly the kind of thing a VPN does - opening an encrypted tunnel and routing traffic through it - so it's a common, overlooked cause across all three failure buckets, not just "won't connect." A VPN connection generally needs at least one port open through the firewall to establish itself at all, as Cloudflare's own explainer on how a VPN works notes, which is exactly what a strict firewall or router blocks by default. Antivirus suites with their own network-filtering feature are frequent culprits too. Temporarily disabling third-party security software, one at a time, and retrying the connection isolates whether this is the cause before you change anything else.
What Do the Most Common VPN Error Codes Mean?
Numbered error codes look intimidating but usually point at one of the causes already covered above. A handful come up constantly: an error in the 800 range typically means the server couldn't be reached at all, often a blocked port; an error in the 600s often points at a device or configuration problem rather than the network; and an authentication-specific code maps directly to the wrong-credentials case above. Microsoft's own reference for these dial-up and VPN error codes is worth bookmarking if you're troubleshooting a Windows client specifically - Microsoft's VPN and dial-up error code reference lists them by number rather than by symptom.
How Do You Verify the VPN Is Actually Working After a Fix?
A "connected" icon is not proof the tunnel is carrying your traffic - it's proof the app thinks it is. After any fix, check rather than assume: the VPN Checker tool confirms whether the connection is actually being read as a VPN, and the IP Lookup tool shows the exact address and location a site would see right now. For the full walkthrough, how to check if your VPN is actually working covers DNS leaks and kill-switch testing as well.
What's the Fastest Way to Reset a Broken VPN Setup?
- Sign out of the app fully, not just disconnect, then sign back in.
- Delete the VPN connection profile and re-add it from scratch, rather than editing an existing one that may be carrying over a bad setting.
- Update the app - protocol and server-list bugs are common causes and are usually the first thing a new release fixes.
- As a last resort, uninstall and reinstall the app entirely, which clears any corrupted local configuration a normal reset doesn't touch.
Frequently Asked Questions
Why does my VPN say "unable to connect" every time?
Most often a blocked port, an incorrect server address, or the server itself being down. Try a different server on the same provider first - if that one connects, the original server was the problem rather than your device or network.
Why does my VPN disconnect every few minutes?
Usually a device power-saving feature pausing the app in the background. Excluding the VPN app from battery optimization in your device settings fixes most recurring drops of this kind.
My VPN says connected but my IP address hasn't changed. What's wrong?
A "connected" status only means the app believes the tunnel is up, not that your traffic is actually going through it. A split-tunneling setting, a DNS leak, or a cached result in the app you're checking with are the usual causes.
Can antivirus software block a VPN connection?
Yes. Antivirus suites with their own network-filtering features often treat a VPN's encrypted tunnel as suspicious. Temporarily disabling third-party security software and retrying the connection is the fastest way to check.
Why is my VPN connection so slow?
Some slowdown from encryption and the extra server hop is normal. Unusably slow points at a specific cause instead - an overloaded or distant server, a slower protocol, or your underlying connection already being the bottleneck.
What does VPN error 809 mean?
It means the connection between your device and the VPN server couldn't be established, most often because a required port is blocked by a firewall or router rather than an issue with your credentials or the app itself.
Will reinstalling my VPN app fix a connection error?
Sometimes, but it's a last resort rather than a first step. Signing out and back in, or deleting and re-adding the connection profile, fixes most of the same problems without losing the app's saved settings.
Final words. Sorting a VPN problem into "won't connect," "keeps dropping," or "connects but does nothing" before touching any settings saves the most time - it points straight at the short list of causes that actually apply, instead of working through every fix on the internet in order. Once it's fixed, confirm it rather than trust the icon on the VPN Checker tool.
