VPN Connection Drops After 25-30 Seconds on FortiClient VPN 7.4.0.1658

[ArieSLV]

Problem:
I am experiencing an issue with my VPN connection using FortiClient. The connection successfully establishes, but it disconnects after 25-30 seconds.

Symptoms:
- After clicking "Connect," the VPN connection is established successfully.
- Data traffic begins with approximately 35KB sent, but received traffic remains at 0KB.
- After 25-30 seconds, the connection drops with the message "SSL VPN Connection is down."

FortiClient Version:
- FortiClient VPN Only 7.4.0.1658

Logs:
- sslvpndaemon_1_error.log:

[2024-08-04 11:01:10.7069198 UTC+03:00] [12232:12956] [sslvpndaemon 540 error] CListener::_ReceiveMessage() Could not read from pipe(0x0000000000000544) client. Error=109
[2024-08-04 11:01:13.5362518 UTC+03:00] [12232:20528] [sslvpndaemon 569 error] CListener::_ReceiveMessage() ERROR_BROKEN_PIPE
[2024-08-04 11:01:13.5363023 UTC+03:00] [12232:20528] [sslvpndaemon 590 error] CListener::_ReceiveMessage() ERROR_BROKEN_PIPE
[2024-08-04 11:01:14.4208549 UTC+03:00] [12232:13988] [sslvpndaemon 569 error] CListener::_ReceiveMessage() ERROR_BROKEN_PIPE
[2024-08-04 11:01:14.4208880 UTC+03:00] [12232:13988] [sslvpndaemon 590 error] CListener::_ReceiveMessage() ERROR_BROKEN_PIPE
[2024-08-04 11:01:35.7225054 UTC+03:00] [12232:19416] [sslvpndaemon 510 error] error: WSAEnumNetworkEvents FD_CLOSE (10053)
[2024-08-04 11:01:40.2707891 UTC+03:00] [12232:6428] [sslvpndaemon 569 error] CListener::_ReceiveMessage() ERROR_BROKEN_PIPE
[2024-08-04 11:01:40.2708176 UTC+03:00] [12232:6428] [sslvpndaemon 590 error] CListener::_ReceiveMessage() ERROR_BROKEN_PIPE

- FortiVPN_1_error.log:

[2024-08-04 11:01:37.6109415 UTC+03:00] [22460:2404] [FortiVPN 2055 error] !!! fortivpn::StateMachine::HandleTunnelDisconnected session 1 (.\[сorrected_for_anonymization_purposes]) "[сorrected_for_anonymization_purposes]" disconnected unexpectedly!

Steps Taken to Troubleshoot:

1. Removed third-party antivirus software: This did not resolve the issue.
2. Disabled Firewall (both third-party and Windows Defender): This did not resolve the issue.
3. Installed the application on my phone: Used the same credentials and the connection worked without disconnections over an extended period (issue not observed).
4. Switched Internet interfaces (from WiFi to Ethernet): This did not resolve the issue.
5. Set up a Hyper-V machine with the latest version of Windows 11 Pro on the same computer where I am experiencing the issue: The connection worked without disconnections (issue not observed).
6. Reinstalled Windows 11 Pro on the problematic machine using the same build as the Hyper-V machine: On a completely clean system, the issue persisted.
7. Used binaries from an older version installed by a colleague: Replacing the current binaries with these did not resolve the issue (unable to find older installation files on the website).

Request for Assistance:
- Are there any additional steps I can take to diagnose or resolve this issue?
- Any suggestions for other potential causes or solutions would be greatly appreciated.

Thank you for your support.

[salemneaz]

Also disable IPv6 at the Adaptor

[salemneaz]

https://community.fortinet.com/t5/FortiGate/Technical-Tip-SSL-VPN-disconnection-issues-when-connecte...

[ArieSLV]

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@salemneaz wrote:

Also disable IPv6 at the Adaptor

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Done. Unfortunately, this did not resolve the issue.

[ArieSLV]

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@salemneaz wrote:

Would it be possible for you to check the same from a different host using the same connection, I am just trying to rule out the issue with the internet connection itself.

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Thank you for your suggestion.

Yes, I have already checked the connection from a different host using the same internet connection. The issue with the internet connection itself is ruled out by the following facts:

1. FortiClient installed on my phone, which is connected to the same WiFi router, does not have this issue, and the connection does not drop.
2. FortiClient installed on a virtual machine running on the same computer does not have this issue, and the connection does not drop.
3. Connecting directly to the FortiGate via Ethernet does not resolve the problem.

[AGU_HD]

Trying installing this Visual Studio Redistributable: https://aka.ms/vs/17/release/vc_redist.x64.exe

The Forticlient VPN Application is trying to start fortitray.exe, but it needs a .dll file to work (mfc140u.dll) which is missing from Windows.

After installing and a reboot, your Forticlient VPN app should work again.

[Servicedesk_Beek]

Goodmorning, I have the same issue. Have installed the latest version and now I cannot login any more: Could not read from pipe(0x0000000000000760) client. Error=109

Anyone has a solution?

[AGU_HD]

Trying installing this Visual Studio Redistributable: https://aka.ms/vs/17/release/vc_redist.x64.exe

The Forticlient VPN Application is trying to start fortitray.exe, but it needs a .dll file to work (mfc140u.dll) which is missing from Windows.

After installing and a reboot, your Forticlient VPN app should work again.