Unable to establish the VPN connection. The VPN server may be unreachable (-20101)

[tomgiet]

Forticlinet try to connect. At 91% get error:

"Unable to establish the VPN connection. The VPN server may be unreachable (-20101)"

Windows 10: up to date

Forti version: 5.6.5.1150

Reinstalled

Firewall and other chacked/disabled

TLS in Internet Explorer Settings ok

Other units form the same net works fine. There is no information about -20101 error in the net.

[Toshi_Esumi]

Is this Win10 app version or FortiClient for Windows version? If the former, try uninstall it then install the latter and try. Behaviors might be different from the app version. And more importantly this one has a feature to take debug log, which you probably need to if even this version doesn't work.

But it seems to be very specific to your Win10, assuming some of working ones are Win10 as well.

[tomgiet]

It is 'standalone' version installer. I have also other problems after last week Windows update, so I decided to reinstall the system. I'll post results.

[Toshi_Esumi]

Then you can run local logging at debug level. That would tell you what it was expecting when it failed.

By the way, when Win updates happen, we sometimes need to reboot the machine twice to complete update process before FortiClient can bring up the connection fully. But those cases, it gets stuck at 98% instead. So I thought your case was different.

[tomgiet]

Reinstall Windows 10 helps :)

[praveenke]

Looks like a kind of windows memory management issue. Following is the details of steps I usually do to get rid of this issue.

1. Restart FortiSSLVPN demon (Services.MSC)

2. Restart FortiSSLVPN Client

The root reason I think, windows client machine used continuously for many days with out restart/shutdown OR machine hibernated/resume for many number of times.

[tioeudes]

Hello tomgiet

Can you post the output of the command "diag debug application sslvpn -1"  ?

1 - run:

diag debug application sslvpn -1

diag debug enable

2 - try to connect;

best regards,

tioeudes