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The PPP link control protocol was terminated

Posted: Tue Dec 29, 2020 3:52 pm
by ibghs
I have set up windows 10 machine with softether VPN server connected to VPN Azure. See
I am using other PCs to connect using windows 10 inbuilt VPN client using SSTP.
The connection fails with "The PPP link control protocol was terminated" unless I modify the propoerties of the VPN adapter to allow unencrypted password (PAP).
According to the SSTP Server Function Specifications on SoftEther VPN Server, it should also use MS-CHAPv2 for authentication. See
But using MS-CHAPv2 fails to connect from multiple machines.

The server spec also states: Compatible VPN Clients: Built-in VPN Clients on Windows Vista, 7, 8, RT
I am using Windows 10.

1. Is MS-CHAPv2 authentication with SoftEther SSTP Server incompatible with Windows 10 client or server?
2. Is PAP unsafe or is there any layer of encryption around the password transmission using the Windows 10 VPN client?
3. Please advise what else to try on either the SoftEther VPN or Microsoft VPN client.

Thank you