Hello,
Is the SEPM installed on Windows XP machine??
This is caused by exhaustion of sessions. Windows XP can only support 10 concurrent sessions.
Solution: You can clear the active sessions to by using the iisreset command.
Also check this Article:
Best practices guide for installing the Symantec Endpoint Protection Manager (SEPM) on a Windows XP operating system.
http://www.symantec.com/docs/TECH91694
You are installing the Symantec Endpoint Protection Manager (SEPM) on a Windows XP machine. Windows XP has a 10 concurrent connection limitation that has been built in by Microsoft. This guide contains the configuration changes that are necessary to work around this limitation. This is supported for up to 100 clients managed from a single XP SEPM.
Hope that helps!!