Issue:
Symantec Endpoint Encryption clients cannot communicate with the server if the alias name is not set as Service Principal Name for the Management Server computer in Active Directory.
When you use an alias for Symantec Endpoint Encryption Management Server with Windows Authentication enabled, add the alias name as the Service Principal Name for the server computer in Active Directory. This action ensures successful client-server communication. Refer to the Microsoft documentation for adding the alias name as the Service Principal Name.