Access to company files in multi-user mode is blocked when the QuickBooks Database Server Manager malfunctions, resulting in the QBDBMGrN Not Running error. This problem frequently occurs as a result of idle services, a misconfigured firewall, or broken installations. Fixing the issue may involve restarting QBDBMGrN and modifying its settings. For expert guidance and support regarding QuickBooks, Call 1.855.738.2784.