The error QuickBooks cannot communicate with the company file can be caused by firewall restrictions, improper hosting settings, or network conditions. The file cannot be accessed in multi-user mode due to this problem. In order to resolve it, you must check your hosting settings, modify firewall permissions, and use the QuickBooks File Doctor tool to identify and address network issues. To speak with a friendly and informed QuickBooks phone support specialist, dial 1.855.738.2784.