Endpoint Protection (SEP) scan completes immediately and shows completed with 0 files scanned
Symantec Endpoint Protection 14.3 RU2 and lower.
This is related to a new certificate being used to sign SDS 1.21 for endpoints running 14.3 RU2 and older, this would require an update to SymVT in order to load the engine successfully.
There are 3 options to resolve the issue.
Then configure SEPM to download updates from this location:
Run the LiveUpdate download task on SEPM and verify it is successful. Then revert to original setting.
Configure the clients to download this content from SEPM.