A Symantec Data Center Security Server Advanced agent goes to the Possibly Offline state if the agent is registered with lower polling interval than the polling interval specified in the Common Configuration policy that is applied to the security group of the agent.
Example: If you add an agent with polling interval of 30 seconds to a security group that has a polling interval of 300 seconds as specified in the default common configuration policy, the agent will be in the Possibly Offline state until the agent polls back to the server. When the agent polls back to the server, the agent becomes Online.
You can resolve this issue by either of the following two ways: