On server stop the service of endpoint wih below steps.
Start->run
smc -stop
Ok
go to C: program files\Symantec\Symantec endpoint protection
Open Sylink.xml file in a word pad.
There will be two instances of Verify signatures and the value will be 1
Make it 0 (please do change anything else. make a backup of this file before you proceed)
Save it and start the services by
smc -start
give it a 10 minute to 15 minute shot to communicate.
That should fix the issue.
Good Luck!