Yep, found the issue on the client side.
They start blocking "Uncategorized websites" on their Sophos UTM Web filtering service, and this triggered the VPN issue. Fixed by excluding my VPN FQDN address on their Sophos Web filtering.
I am having this issue. The first time I tried to open FortiClient VPN, Windows seemed to crash. The screen went blue and there was a :( and a message that said there was an error. My computer rebooted before I could get any message.
Every time I've tried to log in after that, the VPN got to 98% and then it disconnected.
I tried to install a newer version of FortiClient and now the connection only gets to 80% and then I get an error saying the "SSLVPN Tunnel connection failed" and a warning message that says Unable to establish the VPN connection. The VPN server may be unreachable (-14).
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