You are seeing the below error message on your company's integration status, or on your Desktop Sync App.
QB Desktop ErrorMessage: A QuickBooks company data file is already open and it is different from the one requested or there are multiple company files open.
If you are getting the following error below it is due to multiple users working on the same QuickBooks file.
To clear this error, please follow these steps:
Ask all users to close QuickBooks (including yourself).
Once this is done, only you should sign back into the company file.
After this, please attempt to publish an invoice.
The error message will only clear after an invoice is successfully published to QuickBooks.