Main things to check:

Make sure the controller is on and at the main test screen before starting Xy software. Make sure the Xy software is 'run as administrator' The main test screen will say 'C0-M1' in upper left corner of controller screen. This is the screen just past the screen where it asks if you want to zero all, position or Load.
If not able to connect, make sure the USB cable is plugged into the controller and the PC the software is on and that the USB port its plugged into on the PC is a 2.0 port and not a 3.0 port. 3.0 port will have a blue tab, 2.0 will have a black or white tab.
If still not able to connect. Check to make sure the drivers did not get updated. The attached document will show how to walk through checking for the drivers and reverting them if it indeed updated.
If that doesn't resolve then possible a bad USB cable. If you can replace to confirm if it is the cable.
If all above fail then like the controller needs to come back for further evaluation/repair.

Window 10+ users:

Per the attachment on reinstalling drivers you may run into windows error message which may block you from running the .exe installer for the drivers. Below is an alternative step.

Disconnect the PC from the internet if it is connected. Then plug in the USB cable, windows may try to install the drivers automatically from the internet but it won’t be able to and error out.

Open the device manager and expand the ‘ports’. You should see a com port with a little caution sign next to it. Right click on that and select update driver.

Another window will appear to have the windows either search the web or for you to select the folder the drivers are in.

Select the options to browse. In the next window, browse to the drivers folder in Xy and click ok. Then check the box if not checked to search sub folders. Then press ok.

Should find the driver and start the installation process. Once completed in the device manager the com port will say Silicone laboratories and then not have a caution icon next to it. This indicates the drivers were installed correctly.

You can plug the internet back in if it was before. Then go through the xy connection process.