QuickBooks Error H505 can appear when a workstation cannot connect to the QuickBooks company file stored on the server. The problem is commonly associated with incorrect hosting settings, firewall restrictions, missing network configuration, or issues with the QuickBooks Database Server Manager. Check that only the server computer has Host Multi-User Access enabled and that hosting is turned off on workstations. You can also scan the company file folder using QuickBooks Database Server Manager and review firewall permissions. If the connection still fails, call +1(866)-513-4656 for assistance troubleshooting QuickBooks Error H505 and restoring multi-user access between your workstation and server.