An internal QuickBooks error occurred while trying to access the QuickBooks company data file

Problem

You cannot sync with QuickBooks Enterprise.

Description

The web connector shows authentication failed and the web connector is red. Here is the error:

An internal QuickBooks error occurred while trying to access the QuickBooks company data file

Solution

Enter Multi-User Mode

Any single user mode task, like running payroll or bank feeds will cause a sync failure. These tasks put QuickBooks into single user mode. Stop running these tasks and have the user log out of QuickBooks. Log into your QuickBooks company file. Select multi-user mode. Sign in as admin. Run your web connector.