You could be getting this message for more than one reason.

If your organisation uses a a proxy server to connect to the internet, please see article How do I add my proxy server settings to the Enterprise Server?

If you do not connection to the Internet through a proxy server then the reason you may be experiencing this error is because; 

• Your Internet connection may have failed
• The security suites comprising of antivirus is blocking the DESlock+ application from accessing the internet
• The Internet Proxy values are incorrect 

1. To check that you do have an active internet connection, visit the following web page https://stratus.deslock.com using Internet Explorer.  If this page loads, your internet connection is fine and the problem may be caused by another reason listed below. However if you have failed to load this page then please check all network connections and Internet protocols.
2. Some security suites which include Firewalls and Antivirus protection can block the DESlock+ Enterprise Server setup from accessing the internet. The way to resolve this varies depending on which security suite you have installed, however to prevent this, you will need to access your security suite settings, view which applications are being blocked and then add them to the list of trusted programs which are allowed to run and access the Internet.
3. Check that the Internet Proxy values in the Enterprise Server meet those detailed within your internet properties under the connections tab and within LAN settings. In the proxy Server pane you will have the ip address or name of your proxy Server and Next to it will be the number of the port which it uses to connect to the internet. Click the advanced button to see which type your proxy address is assigned to.