Re-enable IPSec 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.
Note. Here is all you need to do if you encounter VPN error 169. What can cause error 789 to return in Windows 7 and 10? Network inconsistency. It turns out that your own network inconsistency can also lead to a specific error message.
You will probably receive an error message “The L2TP connection attempt failed because the protection layer encountered a processing error.” L2TP is a well-known VPN connection that often encrypts and secures data. This is a popular good VPN that uses layer 2 tunneling to bring the protocol closer to the security restrictions of the area.
In this case, it is also due to an inaccurate configuration of your operating system, as in Windows 10. This general error occurs when IPSec negotiation fails for L2TP/IPSec connections. Other possible causes: The L2TP-based VPN client (or VPN server) is behind a NAT. The VPN server or client has the wrong certificate or pre-shared key installed.
On Windows 10/11, whenever you try to connect to a VPN, you see a screen in the bottom right corner of the screen. If you check the Windows logs in Event Viewer, you might see the message I would say VPN failed and the procedure error returned on failure looks like 789.
Is there an error code for VPN error 789?
In most cases, Internet users face various difficulties when trying to use this secure internet connection, and no matter what method of operation you use, there is a high chance of encountering several VPN error codes. Today the VPN discovery error is error 789.
How do I fix Error 800 789 L2TP and setup VPN in Windows 7?
Fix: Error 800 Windows 7 (L2TP in IP Sec client cannot connect)
- In Windows 7, go to VPN connection properties and click Security.
- For l2tp/ipsec, select VPN type, then click Advanced.< /li >
- Select “Use pre-shared key for authentication only” and click OK.

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.