VPN Error 800 - Why It Occurs and What You Can Do

Daily Life In Tehran - Using VPN to Access Social Media
Daily Life In Tehran - Using VPN to Access Social Media. Kaveh Kazemi / Getty Images

A common issue encountered when working with virtual private networks is VPN error 800 - "Unable to establish the VPN connection." Unfortunately this error code doesn't explain why the connection is actually failing.

What Causes VPN Error 800

This issue occurs when trying to establish a new connection to a VPN server. It indicates that messages being sent by VPN client are failing to reach the server.

Many possible reasons for these connection failures exist including:

  • the client device has lost connection to its local network
  • the user has specified an invalid name or address for the VPN server
  • a network firewall is blocking the VPN traffic

How to Resolve VPN Error 800

Check the following to address any potential reasons for this failure:

  1. Is the network connection between client and server functioning properly? You can attempt to ping the server if not sure, although VPN servers can be configured to ignore ICMP requests. Retrying the connection after waiting a minute or two can help rule out sporadic network outages. Attempting a connection from a different client device can also help pinpoint whether the connectivity issue is specific to one client or if it is a widespread problem.
  2. Are you using the correct VPN server name or address? The name a user enters on the client side must match the server name set up by a VPN administrator.  Given a choice, users can opt to specify an IP address instead of a name. It's even more common to mistype an address than a name, however.  VPN servers may also have their IP address changed occasionally, especially those on DHCP networks.
  1. Is your firewall blocking VPN connections? To determine whether a client firewall is triggering VPN error 800, temporarily disable it and retry the connection. Firewall-related failures indicate a need to update the firewall configuration with additional settings specific to the port numbers the VPN on that network is using (usually TCP port 1723 and IP port 47 for Microsoft WIndows VPNs). Home network administrators normally perform these changes on a broadband router.
  1. Does the server have too many clients already connected (i.e., VPN server connection limit exceeded)? Connection limits vary depending on how the server is set up, but compared to other possibilities, this is an uncommon problem.

Related VPN Error Codes

Several other kinds of virtual network failures can occur that appear similar to VPN error 800:

Error 619: A connection to the remote computer could not be established, so the port used for this connection was closed.

This error indicates the client was able to reach the server but still unable to complete the connection process.

See also: Common VPN Error Codes Explained

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