Traffic from Unmanaged SEP for Mac 14.2 client doesn't flow through the system proxy setting during liveupdate. As a result, definitions cannot be updated.
Unmanaged SEP for Mac 14.2
SEP for Mac 14.2 client does not use OS HTTP proxy settings.
This issue is fixed in Symantec Endpoint Protection 14.2 MP1. For information on how to obtain the latest build of Symantec Endpoint Protection, see Download the latest version of Symantec Endpoint Protection.