VPN Is Not Working: Basic Server and Client Troubleshooting Guide

TL;DR

• If your VPN is not working, start simple: check your internet without the VPN, restart the client/device, switch servers, and update the VPN app.
• If the VPN won’t connect, the VPN keeps disconnecting, or the VPN connected but shows no internet, test another device and run ping / traceroute to see whether the issue is client-side or server-side.
• Most VPN connection issues are caused by DNS problems, firewall blocks, wrong ports, or protocol conflicts (OpenVPN/WireGuard).
• Quick fixes: set DNS to 1.1.1.1 or 8.8.8.8, clear the DNS cache, check firewall rules, and verify server status.
• If problems persist, review VPN logs or move to a more stable or dedicated VPN server.

A VPN is a virtual private network that protects your online privacy by masking your public IP address. VPNs are widely used today, and according to Statista, the global VPN market will reach $75.59 billion by 2027, reflecting the growing demand for online privacy and security.

VPNs are useful not only for data security but also for gaining the freedom to access restricted content, work remotely effectively, enjoy entertainment, travel, and more.

However, there's one important caveat: a VPN is only useful if it's working properly.

In this basic VPN guide, we'll cover the most common reasons for VPN failure and step-by-step solutions for VPN troubleshooting, both for the client and server.

How to Check If VPN Works

The easiest way to find out if a VPN is working is to launch the VPN program, connect to a server in a different location — for example, another city, state, or country — and check your IP address. You can find or check your external IP address using various websites or by typing "my IP" into your browser's search bar.

Your internet service provider (ISP) typically assigns a public IP address that contains important information, such as your ISP details and approximate geographic location.

When a VPN is enabled, your public IP address will display different information for your ISP, city, region, and possibly even country. So, if you're in the US but using a VPN in the UK, your public IP address will show a UK location.

If you're using a VPN but still see information about your ISP and current geographic location, your VPN is likely not working properly.

Why VPN Fails

Sometimes, even a reliable VPN can fail, or the VPN keeps disconnecting, due to client-side issues, server problems, or network-related factors. These problems can range from simple to more complex. Here's a list of the most common reasons why a VPN might stop working:

• Unstable or unavailable internet connection
• Overloaded or temporarily unavailable VPN server
• Incorrect credentials or expired subscription
• Outdated VPN client software or version
• Blocked by a firewall or antivirus
• Restrictions from your internet service provider
• Closed or incorrectly configured ports
• Domain Name System (DNS) errors or IP address conflicts
• VPN protocol issues: incompatible or incorrectly selected VPN protocol (WireGuard is not working, OpenVPN is not working)
• Corrupted device network settings
• Incorrect date and time settings on your device
• Conflict with another VPN or proxy service

Understanding where the problem is coming from — whether it's your device, your local network, your internet provider, or the VPN server — will help you resolve the issue more quickly. This can be determined by running a few basic checks.

VPN Test: 8 Quick Checks

Before moving on to deeper diagnostics and technical VPN troubleshooting, try these simple steps:

1. Check your internet connection. Make sure your normal internet connection works without a VPN. Disable the VPN connected to the internet, then run a speed test or visit a few websites.
2. Restart the VPN. Close the VPN client completely and then reopen it. A simple reboot often resolves minor glitches or background issues.
3. Restart your device. Restart your computer, smartphone, or router. This will refresh system processes and resolve temporary network errors.
4. Check your system time and date. If your system time is set incorrectly, you may be unable to log in to the VPN. For example, if your system time is set to January 1, 2023, an SSL certificate issued in 2024 will be rejected, and you won't be able to connect.
5. Change your VPN server or location. Your server may be overloaded or temporarily unavailable. Try accessing a different region or server.
6. Update your VPN software. Make sure you're using the latest version of your VPN client. Outdated software can cause connection or compatibility issues.
7. Try a different VPN protocol. Protocols vary in terms of security, speed, and stability across different network environments. If you can't connect with one VPN protocol, try switching to another in the VPN app. Alternatively, use the automatic switcher feature to choose the best VPN protocol for you.
8. Check the expiration date of your paid VPN subscription. If your paid VPN plan expires, your account will be downgraded to a free plan, which may result in the loss of other advanced VPN benefits.

If your VPN still isn't working after completing these steps, it's time to move on to more detailed troubleshooting on the client or server side.

Client vs. Server Issue?

When your VPN stops working, the fastest way to fix the problem is to pinpoint the source. The key question is simple: is the problem client-side or server-side — specifically, is it with your device or the VPN server? Here's how to determine this step by step.

Step 1: Test the Internet Without a VPN

Try disabling the VPN and visiting a few websites.

• If the internet doesn't work at all, the problem is most likely client-side: related to the client network, ISP, router, or DNS.
• If the internet works fine, the problem is server-side: related to the VPN connection itself.

Step 2: Switch to Another Server

Select and connect to a different VPN server.

• If the other server works, the problem is likely server-side: overload, a configuration issue, or a blocked IP address.
• If neither server works, it could be due to client-side settings, firewall issues, or an ISP block.

Step 3: Try Another Device

Use the same VPN account on another device or network.

• If the VPN works on another device, the issue is specific to the device and may be caused by client-side settings, an outdated app, or a network adapter.
• If it doesn't work on any device, the issue is likely server- or account-related.

Step 4: Run Network Diagnostics

Run a simple test:

ping server_ip
tracert server_ip (Windows) or traceroute server_ip (Linux/macOS)

Interpreting the results:

• No response. This could be due to a server failure, a VPN firewall blocking the connection, or ISP restrictions.
• Routing stops within your local network. This could be a client-side network issue.
• The route reaches the server, but the VPN connection authentication fails. This may be due to a service or server settings issue.

Step 5: Review VPN Logs

Most VPN clients and servers create logs.

• Authentication errors. These may be caused by invalid credentials or an expired subscription.
• TLS errors. These may be caused by certificate, protocol, or port configuration issues.
• IP address assignment errors. These could be caused by incorrect routing or NAT configuration on the server.

Client logs typically indicate issues with local configuration on the client side, but persistent connection drops or service outages often indicate server instability.

VPN Troubleshooting: Client vs. Server

Common VPN Fixes

In this section, we'll cover the most common VPN issues and the diagnostic methods used to resolve them. A table is provided to help you quickly determine whether a more thorough server check is needed or if a client-side fix is possible. We'll also take a closer look at two common causes of failures: DNS configuration errors and IP address conflicts. You'll also find information about VPN blocking by your internet service provider or network administrator, including when and why this happens, and what to do in such situations.

Client/Server VPN Fixes

The following table helps you quickly determine whether the problem can be resolved on the client side or requires deeper server-level troubleshooting.

DNS Issues

VPN issues with DNS settings and IP address conflicts deserve special attention. Troubleshooting client-side issues requires a bit more technical knowledge than simply rebooting the device.

One of the most common reasons a VPN connection appears to be configured, but websites cannot be accessed, is incorrect DNS configuration. If the VPN server is not responding or the client is using incorrect DNS settings, domain names may be blocked.

DNS issues include:

• Incorrectly configured DNS servers on the VPN client
• DNS leaks that interfere with local DNS and VPN DNS
• Incorrectly configured DNS forwarding on the VPN server
• Cached DNS records pointing to outdated addresses

Solutions:

These issues can often be resolved by setting up trusted public DNS servers, such as 1.1.1.1 (Cloudflare) or 8.8.8.8 (Google), and clearing the DNS cache.

Set DNS to 1.1.1.1/8.8.8.8

Setting up third-party DNS 1.1.1.1 (Cloudflare) or 8.8.8.8 (Google) helps bypass ISP blocks and speeds up website loading. This can be done in Windows/macOS via network settings, in Android/iOS via network settings or private DNS, and in Linux via resolv.conf.

To set up third-party DNS, follow these steps:

Windows

1. Open Settings → Network & Internet → Wi-Fi or Ethernet.
2. Click Properties for your connection → Edit next to DNS server assignment.
3. Select Manual.
4. Enable IPv4 and enter:
   Preferred DNS: 1.1.1.1 (or 8.8.8.8)
   Secondary DNS: 1.0.0.1 (or 8.8.4.4)
5. Save the settings.

macOS

1. System Preferences → Network.
2. Select your active Wi-Fi connection.
3. Click Details.
4. Select the DNS tab.
5. Click the + sign and add 1.1.1.1 or 8.8.8.8.
6. Click OK → Apply.

Android

1. Go to Settings → Connections → Private DNS.
2. Select your network.
3. Click connection settings.
4. Select IP Settings.
5. Select Static.
6. In IP Settings, enter DNS 1 as 1.1.1.1 or 8.8.8.8 → Save.

iOS

1. Settings → Wi-Fi.
2. Click the ⓘ icon next to your network.
3. Select Configuration DNS → Manual.
4. Delete the old addresses and add 1.1.1.1 and 1.0.0.1.
5. Click Save.

Linux

1. Open a terminal with Ctrl+Alt+T.
2. Edit the resolv.conf file:

   sudo nano /etc/resolv.conf

3. Replace (or add) the following lines:
   nameserver 1.1.1.1nameserver 8.8.8.8
4. Save with Ctrl+O, Enter, and close with Ctrl+X.

Clear DNS Cache

To clear the DNS cache, follow these steps:

1. Open the command prompt on your device by pressing Win + R (Windows) or Ctrl + Alt + T (Linux), or by clicking the Terminal button on your device (macOS).
2. In the window that appears, enter cmd and click OK.
3. In Windows, run the following command in Terminal:

   ipconfig /flushdns

4. In macOS, run the following command in Terminal:

   sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder

5. In Linux, run the following command in Terminal:

   sudo resolvectl flush-caches

   or

   sudo systemd-resolve --flush-caches

6. On iOS and Android, simply enable/disable Airplane Mode → reboot your device.

Congratulations! Your DNS cache has been cleared successfully.

IP Address Conflicts

If the VPN assigns an IP address that overlaps with your local network, IP address conflicts may also occur. To avoid routing conflicts, VPN subnets should be different from your local network ranges.

Otherwise, the system may incorrectly route network traffic, making VPN access unreliable or completely unavailable.

Typically, such conflicts can be quickly resolved by checking and changing the IP address range on both the server and client. The easiest way to check the IP address is through the command line.

To check the IP address range, open the command line on your device using the method you already know.

ipconfig /all (Windows)
ifconfig (macOS)
ip addr или ifconfig (Linux)

However, if you need to change the IP address on your local network, you'll have to do it manually.

Solution:

Using Dynamic Host Configuration Protocol (DHCP) combined with different subnets for the VPN and local network is the best way to avoid manual IP changes. This automatically resolves most conflicts.

VPN Port Blocked by ISP/Network Administrator

In some situations, a VPN works correctly, but access may be limited or blocked by your ISP or local network administrator.

This can happen in:

• Corporate networks with strict firewall rules
• Public Wi-Fi networks (airports, hotels, universities)
• Places where VPN traffic is constantly restricted

Solutions:

• Change VPN protocols (for example, from OpenVPN to WireGuard).
• Change VPN ports.
• Use stealth VPN modes.
• Connect through a different network.

Prevent VPN Issues: Best Practices

Knowing the source of a problem and fixing your VPN once is a good thing. Avoiding the need for repeated repairs is even better. Most VPN failures stem from common causes, such as outdated clients, overloaded servers, incorrect firewall rules, or improper DNS configuration. These issues can usually be avoided with regular maintenance, and a few preventive measures can significantly reduce the likelihood of future VPN failures.

Here are some recommendations to help you maintain the performance, security, and stability of your VPN when needed:

• Keep your VPN client and server software up to date.
• Monitor resource usage and server performance.
• Use certified and trusted DNS servers.
• Maintain proper firewall and port settings.
• Check VPN logs for warnings or errors.
• Don't run multiple VPNs or proxy services simultaneously.

Regular maintenance and monitoring help detect problems before they impact your connection.

Time to Contact Technical Support

If you've completed all the basic and advanced troubleshooting steps but your VPN connection failed and still isn't working, it might be time to contact technical support.

When contacting support, it's helpful to provide the following information:

• VPN protocol used (OpenVPN, WireGuard, etc.)
• VPN client error messages
• Relevant log documents
• IP address and server location
• The steps you've already taken

Detailed diagnostic information will help support specialists quickly identify the problem and offer an appropriate solution.

When to Consider Using a Dedicated Server

Sometimes the problem isn't with the VPN server configuration, but with its infrastructure. If your VPN server frequently experiences slow speeds, frequent disconnects, or unstable connections, it could be due to insufficient server or shared hosting resources. VPN performance can also be impacted by overloaded servers, limited network ports, or aggressive traffic shaping.

In such cases, the best and inevitable solution is to upgrade to a dedicated or more powerful VPS. This will help ensure stability, improve network throughput, and give you more control over firewall and network settings. A properly configured server with sufficient CPU, RAM, and network bandwidth ensures a reliable connection and consistent VPN performance.

Reliable dedicated and virtual private servers by is*hosting have premium customer support, constant quality control, over 50 thousand active customers, and more than 20 years of experience.

Conclusion

If your VPN stops working, don't panic. In most cases, the cause is a simple DNS issue, a blocked port, or a client malfunction. Start with basic checks and move on to more in-depth diagnostics if necessary. By applying a structured VPN troubleshooting strategy and maintaining a proper VPN configuration and infrastructure, most connection issues can be effectively identified and resolved.