QuickBooks Error 6123 After Update

What types of QuickBooks Error 6123, 0 and why its occurs the steps to fix 6123 error code while using QuickBooks Desktop Pro, Premier , Enterprise or Non profit edition . The error 6123 usually comes when user trying to open QB company file in upgraded version from old version backup .The warning message user see on the screen “QuickBooks Error 6123 Cannot Contact The Database Server” . Also how to get rid off QuickBooks Restore Error 6123 while using Windows 7,8 or 10.