You may download the QuickBooks connection diagnostic tool by following the instructions described below:
First, click on the QuickBooks connection diagnostic tool's official download page.
Going to follow that, Save the file to your system.
After that, run the installer named QuickBooks_Install_tool_vs.exe.
Next, close all background apps that are running.
After that, restart the software and go to the next stage.
Avoid any further errors by ensuring you have a stable Internet connection.
After following that, you must clear all background running applications.