When QuickBooks Database Server Manager is unable to establish a connection with the company file, the error QBDBMgrN not running on this computer appears. Workflow is disrupted and multi-user access is prevented. Damaged files, out-of-date services, and firewall settings are typical culprits. Restarting services, upgrading QuickBooks, and correctly configuring network settings are necessary for fixing. If you need professional QuickBooks phone assistance, call 1.855.738.2784.