Forticlient VPN client on Windows and Linux not showing Certificate Confirmation pop up

[rightclick000]

I have had two recent incidents where after installing the FortiClient VPN client, one on Windows and one on Ubuntu, where after entering the necessary IP address, port, username, and password the pop up window to accept the certificate never shows. 

Is there a way to get the cert from the Fortigate and manually install this or somehow force this pop up window to appear?

[AnthonyH]

Hello rightclick000,

In the FortiGate you may have to enable certificates under System -> Feature visibility. You can then download the Fortinet_CA_SSL certificate and import it into the computer certificate store.

For the warning not prompting anymore:
1) Do you have "Do not Warn Invalid Server Certificate" enabled in the Forticlient Settings?
2) Could you try shutting down the FortiClient VPN?
3) And lastly reboot the Ubuntu machine.

[rightclick000]

Thanks for the suggestions. 

the do not warn box is clear, unchecked in the client.

the client and the laptop have both been restarted, shutdown and started up again. 

Where would the certificate normally be saved for the client?  On a working laptop i'm not finding it in either the User or Computer certificate store.

[Umer221]

For FortiClient VPN, certificates typically aren't stored directly in the FortiClient application itself; rather, they are stored in the system's certificate store.

Certificates tied to the user's account are often stored here under Current User > Personal > Certificates. However, if this is missing, it could mean the certificate is stored elsewhere or was never installed for this specific user profile.

[rightclick000]

Something I tried successfully on the Windows problem was to install the trial version of the full Forticlient.  After installing this the certificate pop up appeared.  I was able to uninstall the full version and log in successfully with the plain VPN client. 

Still waiting to test on the Ubuntu problem.