As more people realize the importance of using a VPN for their everyday Internet activities, the technology is becoming increasingly mainstream. Following the termination of net neutrality in the US and revelations that Cambridge Analytica secretly used Facebook users’ data to manipulate, among other things, the US election, a growing number of people turned to VPNs.

VPNs work by encrypting your Internet traffic and thereby making it impossible for your Internet Service Provider, law enforcement agencies and criminal hackers to see your online activity. Furthermore, the technology is relatively simple to use, which is another reason why its popularity is growing. It’s no longer technology used only by companies.

However, even though using VPNs is fairly easy, you’re likely to run into problems from time to time, as is the case with any technology. Most of these problems can be avoided simply by making sure your VPN app is updated as soon as the updates for your VPN and router are released. Some of the issues persist, though, and that is what this article is for: helping you troubleshoot common problems with VPNs.

Here, we take a look at the 6 most common VPN errors and how to troubleshoot them.

  1. Error Code 807

This disconnection error is common. It’s an indication that the connection between the VPN server and your client device has been interrupted. Some of the causes of this error include:

  • A firewall is blocking the connection
  • A local firewall or antivirus is hampering the connection
  • The VPN server has reached full capacity and is overloaded
  • Your device’s system cache has been overloaded
  • Your Internet connection is faulty or slow

Issues with the VPN transmission can be the problem. However, overloading of the VPN server or latency in your Internet connection is the most likely cause of this error.

Troubleshooting tips:

  • Temporarily disable the antivirus on your device
  • Check the performance of your Internet connection to determine whether the issue is local. If so, restart your router and/or reconnect your local network.
  • Clear cookies and history on your browser.
  • Temporarily disable your local firewall.
  1. Error Code 800

This error is also common. It happens because of an interruption in the VPN server remote connection. It might be an indication that it’s not currently possible to reach the server but the issue is typically caused by one of the following:

  • A firewall is blocking the connection
  • An invalid IP address or name of the VPN server
  • Incorrect security and configuration settings within the VPN software
  • The client device’s connection to the local area network has been terminated

Troubleshooting tips:

  • The first step to dealing with such an error is checking the Internet or network connection. If that’s not the problem, then the issue is with the VPN connection.
  • Ping the VPN router (if it’s allowed by your VPN service).
  • Check whether the name of the VPN and the login credentials are all correct. Make sure that the server name doesn’t include the letters “HTTP” because server names are not URLs.
  • Check whether the settings for the firewall and router allow for VPN or PPTP pass-through. For this to happen the GRE protocol and TCP port 1723 are opened and enabled.
  1. Error Code 691 or 812

This is a VPN/RAS error. It’s usually stated as follows:

“Error 812: The connection was prevented because of a policy configured on your RAS/VPN server. Specifically, the authentication method used by the server to verify your username and password may not match the authentication method configured in your connection profile. Please contact the Administrator of the RAS server and notify them of this error.”

It’s usually an indication of a problem with authentication.

Troubleshooting tips:

  • Check that you’ve used the login credentials
  • Make sure your primary DNS is nested within a joined domain
  • Make sure the secondary DNS is set to an external domain like Google’s 8.8.8.8
  • Disconnect the VPN, give it a few moments and then reconnect
  1. Error Codes 835 and 789

These errors involve failed L2TP connection attempts. Error 835 is an authentication issue whereas 789 is a processing error that occurs during the first communication attempts with the remote VPN server.

Troubleshooting tips:

  • Make sure you have installed the VPN certificate in your device
  • Make sure that the device client you’re using is not covered by a NAT-enabled firewall
  • Reboot the client or the IPSec services
  • Restart the VPN
  1. Error Code 628

Sometimes referred to as Modem Error 628, this is a connection error, typically stated as follows:

“The connection was terminated by the remote computer before it could be completed.”  It could indicate that the underlying connection is problematic or that something on the local device is disrupting the connection. 

Troubleshooting tips:

  • Ensure that you're using the appropriate login credentials
  • Check the Internet connection or local network connection
  • Make sure the settings for your firewall or router are set to allow for VPN and PPTP pass-through. For this to happen the GRE protocol and TCP port 1723 are opened and enabled.
  • Temporarily disable the firewall and local antivirus settings
  1. Error Code 619

This is another connection problem. It is stated as follows:

“A connection to the remote computer could not be established so the port used for this connection was closed.” 

The error happens when your device client tries to connect with a VPN server. Another reason that it might happen is as a result of an abrupt disconnection during a VPN session.

Troubleshooting tips:

  • Reboot the VPN
  • In case you have more than one VPN installed on your device, check the setting of both VPNs to ensure that they are not conflicting. If you’re using a PC, check Windows services or active programs.
  • In case you’re using a Windows PC, confirm the security settings and reconfigure the VPN type to automatic for PPTP. Additionally, you can alter the configuration of the data encryption to ‘Optional’ and choose ‘MS-CHAP v2’.
  • If the problem persists, uninstall the VPN and reinstall it
  • If you have any firewall or antivirus software on your client device, disable it temporarily