Several workstations on a SBS 2003 domain frequently go offline and cannot connect to domain resources. They receive a message and notification icon that says 'working offline' 'nameofsbsserver is unavailable'
Sometimes they are able to click the offline icon and reconnect after a few minutes, other times they cannot reconnect for several hours. This is happens on both XP and Windows 7 workstations intermittently.
When offline, they still have access to internet. There is only one quality switch in between the clients and the SBS server, and the cables are tested as good. What might be causing the problem?