There are a few reasons this error can occur.
QB Company File Path Has Changed
Vinosmith will maintain the path to your company file, which is the absolute path to the QB Company File on your Windows hard disk.
An example value might be:
C:\Users\Public\Public Documents\Intuit\QuickBooks\Company File\Acme.qbwIf you move/copy the company file to a new place on your disk, you will need to let Vinosmith know so the setting can be updated in Vinosmith.
Insufficient Permissions
When the Web Connector is initially installed & configured, it is required to be allowed to run as the Admin user with control of "Always Allow" [Access, even when not running]; as directed in Steps 7 and 8 in:
https://vinosmith.groovehq.com/help/how-do-i-install-and-configure-the-qb-web-connector
This error can occur if these permissions are not granted at the time of original configuration.
To fix these permissions after the WC has been installed:
Open QB in Single User Mode and log in as an Admin
Go to Edit > Preferences
In the Edit window, click on Integrated Applications on the left, then click on the Company Preferences tab on the right.
Click on the row for Vinosmith to highlight it; then click on the Properties button.
On the next screen, ensure both of these options are checked:
Allow this application to read and modify this company file
Allow this application to login automatically
Save / OK all the way out of these screens and try again.