While performing Always On VPN evaluation testing with the latest release of Windows 10 (2004), a bug was discovered that may result in failed VPN connections, but only under certain conditions. Specifically, the failure occurs when both the device tunnel and user tunnel are configured on the same client, and the user tunnel is configured to use IKEv2 exclusively.
Error 829
After upgrading to Windows 10 2004, and when the device tunnel and user tunnel are both deployed and the user tunnel is configured to use IKEv2, the administrator will notice that if the device tunnel connection is established, the user tunnel connects successfully but is then terminated abruptly with error code 829.
Note: This can happen in reverse if the user tunnel is established before the device tunnel for some reason. In this scenario the user tunnel would be connected but attempts to establish the device tunnel would result in failure.
Error 619
If the user tunnel connection is initiated using rasdial.exe or rasphone.exe, the error code returned is 619.
Workaround
The workaround for this issue is to either use a single tunnel, or if both user tunnel and device tunnel are required, configure the user tunnel to use the SSTP VPN protocol instead of IKEv2.
Additional Information
Windows 10 Always On VPN Device Tunnel Only Deployment Considerations
