This warning message only occurs in the following scenarios and can only be seen when selecting the hub from ActivManager/Manage Connections.

1.  When a user tries to connect to the hub which is already connected by another user - another teacher is already connected to that virtual hub and is session or forgot to release the VH.

2.  Network Connectivity Issues - verify there are no firewalls or IPS that are blocking traffic specific to that virtual hubs ports.