When posting time or exchanging information with QuickBooks – A modal dialog box is showing in the QuickBooks user interface
Access QuickBooks on the server and close the message box/window that is currently open within QuickBooks – most of the time this window could be a reminder, the Application Permission window, or some other window that is seeking permission or assistance from you before it can continue. Once you close that window, switch back to the integrated application.
You will then be able to exchange information.
This is a common QuickBooks message. For more information please see their Knowledge Base item posted here