If you get this error while trying to connect to the SSL VPN, it could be because there was an improper logout in the previous session and some of the processes did not close properly. Verify if any of the SSL VPN processes are running. For more information on how to verify this, see Section A.8, Verifying SSL VPN Components.
When this error occurs, manually kill the process if you are an admin or a root user of the machine. If you are a non-admin or non-root user of the machine, restart the machine.