Possible Causes of VPN Error 789 in Windows 7/10 On one side, it could be an indication that your computer is wrongly configured to connect to the VPN. On the other side, it could be an indication that the VPN being used is not functioning correctly, and therefore, rejecting connections from the PC.
According to reports, the VPN error 789 can happen on your Windows 7/8/10/11 PC if you disable essential services for self-hosted VPNs. To fix the error, re-enable them. Step 1: Press Win + R, type services.msc to the box and click OK.
When I try to successfully connect to the VPN connection at my workplace, I get the confusing message 789: The L2TP connection attempt failed because the entire security layer encountered an extension error during the initial negotiation with the remote computer. I am using lp2/ipsec.
The pre-shared key can only be configured if this setting is set to L2TP IPSec VPN or Automatic. Click if you want to select the Use pre-shared key to work with authentication check box. Enter a large value in the Pre-Shared Key field. This value must match the pre-shared key value entered on the VPN-based server.
Can a Windows Server 2003 VPN use a preshared key?
If you’re using a different Windows Server 2003 VPN client as well as a third-party VPN server, you can follow the steps in the Set up a pre-shared key on the VPN client section of this article, but you’ll also need pre-shared keys from the third-party device. In Control Panel, double-click Network Connections.
Can a preshared key be used on a PPTP VPN?
IPSec settings may not be available if the VPN type on the Network tab is actually set to PPTP VPN. Pre-shared key can only be configured if this setting is set to L2TP VPN ipsec or Automatic. Select the Use shared key for authentication check box.
How to configure a preshared key on a VPN?
Configure a unique pre-shared key for the VPN control in the Panel, double-click Network Connections. In the online circle under “Virtual Private”, right-click on the connection for which buyers want to use Advance Shared Advice, then click “Properties”. Frequently click on the “Security” tab.
How to set up a preshared key for a VPN?
We can configure Pre-Shared Property Keys step by step: Open Network and Expense Center – right click VPN connection, Properties – select type L2TP VPN – Advanced – Settings Use Preshared Basic for it, authentication – enter pre-shared key.
Where can I Find my SonicWall VPN preshared key?
Maybe serverfault.com/questions/664580/… is relevant. If you are probably using SonicWall’s global VPN client as mentioned in @yagmoth555’s answer, you will probably find a Connections.rcf file in C:\\Users\sername\\AppData\\Roaming\\SonicWall\\Global VPN Client (source) is known to contain an encrypted version of the pre-shared key.
Can you use preshared key on an IPSec VPN?
Yes, you can use a pre-shared key when deploying an IPSec VPN. You can specify it exactly in the “Authentication” tab, as shown in the image above. However, Microsoft recommends using pre-shared key authentication not only because it is a relatively weak authentication method. See “Don’t Pre-Share Fencing Keys” in this article:
Is there an error code for VPN error 789?
Quite often, internet enthusiasts run into various issues when trying to establish that secure connection, and no matter what operating system you are likely using, there is a high chance of encountering multiple vpn error policies. Today, the false positive is actually VPN error 789.

Ermias is a tech writer with a passion for helping people solve Windows problems. He loves to write and share his knowledge with others in the hope that they can benefit from it. He’s been writing about technology and software since he was in college, and has been an avid Microsoft fan ever since he first used Windows 95.