There is an error in the log similar to this:
This error comes directly from the Intuit Software Development Kit (SDK) and indicates that another QuickBooks user has logged with the same name as the user name you assigned for QQube to auto-login to QuickBooks.
There are two possible causes:
Cause 1. Create the special QQube user per our How-To Guide, to connect to QuickBooks, and ensure that no other person logs in as QQube to use QuickBooks.
Cause 2. There are several reasons why this would have occurred.
What happens in either of these cases is that you have more than one synchronizer running, thus confusing the QQube synch process.
To fix the first possible reason under Cause 2, you need to uninstall from the person who orignally installed QQube under their name - ensuring that they have administrative rights for the uninstall process (do not right click and "Run as Adminstrator") Then reinstall under the either the dedicated synch user in a multi-user environment, or the desired user on a workstation in a single-user environment. See https://clearify.com/wiki/view/157/installation
To fix the second possible reason for Cause 2, you need to do two things: (Only for versions earlier than 7.x)
is requesting access to a wiki that you have locked: https://clearify.com/wiki/view/3694/error-80040437-user-already-logged-in