How Can I Fix QuickBooks Error H505 in Multi-User
https://www.linkedin.com/pulse/how-can-i-fix-quickbooks-error-h505-multi-user-mode-robert-mark-vnmxc
QuickBooks Error H505 can appear when you try to open a company file in Multi-User Mode. In simple words, QuickBooks is having trouble connecting your computer to the computer where the company file is stored.