New user here - just stated using today.
I am at work trying to monitor the two cams we have set up (each built-in iSight cams on MBPs). Both of these have timed out or stopped working after 60 minutes, resulting in the "No Sources Found" error.
It timed out this AM so when I went home for lunch today, I checked the sleep/power settings on the laptop. Both are now set to "never" sleep - I thought that may have been the issue. It happened again, though, after running for 60 minutes after I left from lunch.
I had a thought though - I feel like all the machines on the network are set to renew their DHCP lease every 60 minutes. Could this be an issue? The caveat to that theory, though, is that each machine has a static IP assigned to it, so even if it was renewing the lease every 60 minutes, it should have the same IP as before.