This could be so many things. Does this message happen immediately or is there a pause before the message occurs. This may be a connectivity (firewall) issue, or that the server is not actually running. My recommendation is start with getting an updated version of the product.

Version 12.07 was released February, 2012 and therefore predates Windows 10 and Windows Server 2016 by four years. Both of those operating systems have tightened security, so this could be a firewall issue. While I wouldn't suggest it for production use, you could try setting Windows 7 compatibility mode on the data client and data server to see if that makes a difference. That won't help with a firewall issue though; you could also try to unblock port 1583 if your security policy allows it to see if that helps.  Also, are you running antivirus or internet security software that might be interfering? Finally, it's always worth checking the system event log with the event viewer to see if anything was recorded.

The right answer is to upgrade to a version that supports Windows 10, which will save a lot of time and effort.