"SSL VPN Connection Issue with FortiClient 7.4.1 on Windows 10 (LTSC 1809)"

[N_W]

I have a 200F FortiFirewall device running FortiOS version 7.2.9 at the location. On the Forti SSL VPN tunnel side, we are using domain adcheck by examining the user's registry. If the machine is not part of the domain, it cannot establish an SSL VPN connection.
On Windows 11 machines, FortiClient version 7.4.1 works without any issues. However, on a machine running Windows 10 (LTSC 1809), after installing FortiClient 7.4.1, SSL VPN connection fails. After entering the username and password, it throws me back to the login screen, showing empty fields for the username and password, and does not connect.
The only difference between the machine that works and the one that does not is the operating system. I couldn't find anything related to this issue on the Forti side.
What could be causing this issue?

[AEK]

Please try update your FortiClient to 7.4.2.

[N_W]

Hi, we tried version 7.4.2 but the result did not change.

[AEK]

Hi N_W

• Try install Visual C++ Redistributable on your windows client if not already done
• Also try using Ethernet cable instead of WiFi, to see if it is related to WiFi driver. In case you don't have wire connection then try use another WiFi adapter or driver