Excel add-in 12, access ALM server via VPN

Hi all,

I am working on ALM Client via VPN.

I would like to export tests from Excel to QC using Excel add-in : ALM version 12..20, Excel add-in version 12.20

But when I tried to login ALM with URL  https://<server-name>/qcbin , It always response "Unable to connect ALM server..".  Does anyone experience the same issue? Is there any workaround to connect ALM via VPN?

Thanks a lot for your suggestions!

Have good day!