Hello,
It seems this issue is happening only on 1 machine, correct.
In your, case it clearly indicates that the SEP client is not installed properly or the installation is Corrupt.
If we check the SEP clearly,
Download Insight Failure is caused because Proactive Threat Protection is not working properly, Proactive Threat Protection is not working properly because File System Protection is not working properly. All these Features are Inter-related.
Check this Article: http://www.symantec.com/docs/HOWTO55268
Again, what happens if you move the cursor from 9 to 5 in the Download Insight Policies??
Also to note that the SEP client system must be rebooted after installation to completely activate all components.
Or you may stop the SMC service by the command "smc -stop" followed by starting the service again with "smc -start".
Hope that helps!!