QuickBooks Error H505
According to Intuit, an error code H505 indicates that extra settings need to be made on the computer where QuickBooks company files are stored. QuickBooks Error Code H505 appears when QuickBooks on the user's computer fails to connect to the computer hosting the company file.
Read here: https://quickbookserrorsh202.medium.com/what-is-quickbooks-error-h505-and-how-can-it-be-fixed-1e43b7de2e86
lewis hamilton commented
If you see Error H101, H303, or H505, one or more of your workstations is set to be the server for QuickBooks. Your server (the computer that hosts your company files) should be the only computer set to host multi-user mode. The Host Multi-User Access option should be turned off on your workstations.