I have a file server running Windows Server 2003. Our QuickBooks company files are hosted there for multi-user network access. Everyday around 2 PM, when our accountant tries to switch between company QuickBooks files, an error message pops up saying that the network drives can't be accessed. They can't be accessed by any computer on the network. Our accountant switch files within QuickBooks multiple times a day, it's around 2 PM that the network access to shared drives on the server fails. Reboot fixes the problem temporarily.
What could be causing this?