After upgrade or newly install Symantec Endpoint Protection (SEP) for mac 14.3 RU5 Unmanaged client, SEP is not updating definitions and shows "LiveUpdate Connection Error" when proxy is in use.
Prior to 14.3 RU5, LiveUpdate attempts to access https://liveupdate.symantec.com first, but LiveUpdate does not support using OS HTTPS proxy currently, so it fails. Next, LiveUpdate attempts to access http://liveupdate.symantec.com using OS HTTP proxy, which is successful.
In 14.3 RU5, LiveUpdate attempts to access https://liveupdate.symantec.com only so LiveUpdate does not succeed.
Broadcom is aware of this issue and will update this document when a solution becomes available.
Run following command in terminal then run LiveUpdate.
sudo cp /Library/Application\ Support/Symantec/Silo/MES/LiveUpdate/Backup/Init/datastore/luxds.dat /Library/Application\ Support/Symantec/Silo/MES/LiveUpdate/datastore/luxds.dat