One of the common errors encountered by QuickBooks users is that QuickBooks cannot communicate with the company file due to a firewall. The user's connection to the company file is blocked by the Windows firewall, which results in a server communication issue. The company file is often saved on the Server computer, also known as the Host computer, which users must access from their workstations when QuickBooks is configured to run in multi-user mode. The server, which resembles a massive workstation with high configuration and lightning-fast speed, houses the organization's most important data.