This is caused by an inability to look up the SSL certificate information or to resolve names over the internet.
Make sure that the browser (i.e. Internet Explorer or Safari) is the correct version (or higher version) and that the browser supports 128 bit cipher strength or higher.
The problem could be that there are incorrect settings in the network adapter, TCP/IP settings. Check that the IP, subnet mask, and DNS addresses are correct and if using DHCP that the DHCP server is functioning properly and is returning the correct settings.