Symantec's reason why it fails:
When you logon to the A machine as administrator the SEPM runs using the
local sysytem account. In the Windows Server 2008 r2 if you try to
deloy any SEP package using local system account from SEPM ,it will not
have the access to Remote registry of the client and you will get
"Access denied" which can be seen in the logs. Therefore running the
SEPM using the Administrator Credentials for SEPM services manualy will
give access to the remote registry of the client.
How to fix this:
Click Start -> Run -> Type services.msc -> Scroll down to Symantec Endpoint Protection Manager ->
Double click the service -> Click the Log-on tab - > Select This account fill out your information.
Click Ok and restart the service. This should now work on the machines it was failing on.
Source: Link Link