Hi,
Windows is not great at handling situations where the client and / or server (MX) is behind NAT, and this will generate an 809 error. I am also seeing that, recently, the Windows VPN client does not report the specific numerical error, but reports "The network connection between your computer and the VPN server could not be established because the remote server is not responding."
This can be resolved with a registry edit, which can be tricky to apply. However, you can download the regedit file here
The link also contains advice on resolving other Windows client VPN errors. Hopefully you will find this helpful 😊
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