If you are trying to open the company file that is not in your computer, then the error code H505 occurs in the QuickBooks. There can be various reasons for the occurrence of this error, be it damaged or incorrect.ND file restricts in opening the QuickBooks files. It can also occur when the QB services such as QBCF Monitor and others are not activated in your system. Once you know the reason, then only you can try to fix the issue. If you want to take the assistance of the experts, then you can call QuickBooks tech support phone number that stays accessible at all 24 hours in a day without any fail.