I know that this thread is old, but I've had this problem.
In my case,
1) I wanted to download a Powered Off VM that lives on an ESX Server
2) Using VMware Workstation running on a PC
The ovftool used by VMware Workstation could not resolve the ESX Server by FQDN which caused the error. Even if my PC could successfully nslookup the ESX server by FQDN, cURL was not happy.
I had to add the IP/FQDN details directly in the PC's "etc/hosts" file and it worked.
That's unfortunate but that solved my issue.
Teiva