Hello,
Installing the Symantec Endpoint Protection client for Mac covers both managed and unmanaged installations. Push deployment from the Symantec Endpoint Protection Manager (using the Client Deployment Wizard) is supported as of Symantec Endpoint Protection 12.1.5.
Do you have MAC OS 12.12 (Sierra)? SEP 12.1.6 MP6 Mac client adds support for macOS 10.12. In that case you will have to upgrade from 12.