Export button not working (swingbox upgrade to 14.1)

In  a clean 14.1 SDM (Service Desk Manager) environment, upgraded from 12.7 through swingbox method. Everything during upgrade went as expected, however the export button is not working in the 14.1 environment. In Firefox, when the export button is clicked, nothing happens. In Internet Explorer, when the export button is clicked, a warning "only secure content is displayed".

SDM has been installed with server name using FQDN ( fully qualified domain name).

But the SERVLETs in NX.ENV still pointing using hostname.

Change both @NX_SERVLET_SERVER_URL and @NX_LOCAL_SERVLET_SERVER
to point to the HTTPS URL. Example https://<fqdn>:8443