There are a lot of VPN errors out there.
Way too many, right?

Quick fix

The error message “Unable to establish connection” with error code 800 is a common VPN error. It occurs when the VPN client is unable to reach the server. This error is often caused by a problem with the network connection, for example when the network is down or overloaded.

If you are facing VPN error 800, check your network connection. If the connection seems fine, you can also solve the problem by updating your router firmware, and by making sure that the settings of your VPN client are correct.

Best solution:

https://www.lifewire.com/vpn-error-codes-explained-818197

Quick fix

Are you facing error code 691 or the error message “Access denied because username and/or password is invalid on the domain” while trying to use your VPN account? Then you have most likely entered a wrong username or password.

To solve the problem, ensure that both your username and password are correct. Also note that to authenticate to your VPN, you need to enter the PPTP password instead of your account password. You can find the PPTP settings in the VPN control panel.

Best solution:

https://support.hidemyass.com/hc/en-us/articles/202722196-Common-VPN-Error-Codes

Quick fix

Error 633 is one of the most common VPN errors. The error code indicates that there is an issue with your connecting VPN device. It is almost always caused by a wrong configuration of the VPN device or by the connection being already in use.

If you are facing VPN error code 633, there are several possible solutions to get rid of the problem:

1. On the error page, click on the “Diagnostics” button. The built-in diagnostic tool will now allow you to use the “Repair” option. In some cases, this tool can solve the problem automatically.
2. Another option is to stop and then restart the Remote Access Connection Manager service.
3. You can try so fix the problem by rebooting your system and the VPN connection.

Best solution:

https://www.thewindowsclub.com/vpn-error-codes-troubleshooting/

Quick fix

This error message is common with the Cisco VPN client. It occurs when the network fails and an active VPN connection is suddenly disconnected. It can also be caused by a firewall interfering with the connection.

If you are facing VPN error 412, get rid of the annoying error message by making sure that nothing interferes with the network connection. If you are using a firewall, change the settings to allow your VPN to work properly.

Best solution:

https://www.lifewire.com/vpn-error-codes-explained-818197

Quick fix

Another common VPN error is error code 720, or the corresponding message “No PPP control protocols configured”. This error indicates that the client does not have sufficient protocol support to communicate with the server. It is commonly caused by corrupted miniports.

In order to solve the problem, access the Control Panel. Enter the System configurations an open the Device Manager. The Control Panel will now show you all network adapters. To fix the problem, uninstall the miniport client adapters. Then click on the “Scan for hardware changes” button to populate with new miniport adapters.

Another possible solution is to reset your network in the control panel, then reboot your computer and connect the VPN again. If the error message persists, try uninstalling and reinstalling mini ports as described above.

Best solution:

https://support.purevpn.com/error-720-a-connection-to-the-remote-computer-could-not-be-established

Quick fix

The error code 809 occurs when the network connection between the VPN server and your computer cannot be established. When the remote server is not responding, try the following quick fix solution to enable the port.

• PPTP port (TCP port 1723) is blocked by a firewall/router. [Applicable to tunnel type = PPTP]
• L2TP or IKEv2 port (UDP port 500, UDP port 4500) is blocked by a firewall/router. [Applicable to tunnel type = L2TP or IKEv2]

If you are not able to enable the port, try deploying SSTP based VPN tunnel on the VPN server and the VPN client to allow a VPN connection across the network.

Best solution:

https://support.purevpn.com/error-code-809

Quick fix

This VPN error occurs with many VPN clients when a firewall or a port configuration prevents the VPN client from connecting to the computer.

When this error message appears, try these troubleshooting procedures:

1. If you have more than one VPN client installed on your computer, make sure that only one of them is active, as several clients may interfere and cause the problem. Once you have disabled all active connections, reboot the computer. Your VPN client should now be able to connect to the computer.
2. VPN error 619 can also be caused by a firewall or antivirus software blocking the access to the VPN port. Change the settings of your firewall or disable the firewall and restart the VPN client.
3. If none of the above helps, try uninstalling and reinstalling the VPN client settings. In some cases, a reboot can easily fix the issues.

Best solution:

https://www.lifewire.com/vpn-error-619-3971321

Quick fix

Error 721 is a Microsoft VPN error message indicating that the VPN connection could not be established. Typical error messages are “The computer did not respond” or “Remote PPP peer or computer is not responding”.

This VPN problem usually occurs when your network does not allow PPTP port 1723 or GRE packets. To solve the issue, check your router settings and make sure the required ports are allowed and that the pass-through option is enabled. After changing the settings, try again to establish the VPN connection.

Best solution:

https://support.purevpn.com/error-721-remote-ppp-peer-or-computer-is-not-responding

Quick fix

Error 609 is one of many typical VPN errors on Windows 10. It occurs when a device type that does not exist was specified or when your Windows operating system is corrupted. When dealing with this VPN error, you may also experience crashes and freezes while running applications on your computer.
 

The error can by caused by a misconfiguration of the connecting VPN device, registry errors, malware, corrupted files, and more. As there are several possible causes leading to error 609, the necessary troubleshooting steps may vary.
 

1. The first quick fix solution is to simply reboot the system. If this does not solve the problem, continue with the next step.
2. Use the repair option of the Windows built-in diagnostic tool. This may automatically fix the problem if the VPN error is caused by a missing miniport.
3. Disable the Remote Access Connection Manager (rasman) service in the settings, then check if the error persists.
   
   

Best solution:

https://www.thewindowsclub.com/vpn-error-609-on-windows/

Quick fix

Are you facing error code 789 while using a VPN on Windows 10? Then you are most likely dealing with a connection failure caused by your system not being properly set up to connect to the server.

To quickly solve the problem and to get rid of VPN error code 789, follow these steps:

1. Ensure that L2TP and IPSec pass-through options are enabled from your router, as this may cause the problem on your computer.
2. Reset the network adapter in the Device Manager.
3. Check the certificate or pre-shared key on the VPN server and client side.

Best solution:

https://windowsreport.com/vpn-error-789/

Quick fix

Error 812 is one of the less common VPN errors. However, if you are one of the few users facing this error, try the following solutions to fix the VPN error 812 on Windows 10.

1. Change the VPN client. Using a different client may quickly solve the problem.
2. Simply bypass error code 812 by changing the Primary DNS to Domain Controller. Then access the Secondary DNS to set up an External DNS. For the Primary DNS, select the range as 8.8.8.8, the restart your VPN client.
3. Check the tunnel type settings.
4. If the above solutions do not work, contact your network administrator or your VPN provider.

Best solution:

https://windowsreport.com/fix-vpn-error-812/

Quick fix

This error pops up if one or more devices, for example your firewall or router, are not configured to allow Generic Routing Encapsulation (GRE) protocol packets.

To get rid of error message 806, check the settings of your firewall and antivirus software, or temporarily disable the software or firewall to allow the VPN connection to be established. Another possible solution is to change the port configurations in TCP Port 1723 in Windows 10 to allow the connection.

Best solution:

https://windowsreport.com/806-error-vpn-gre-blocked/