Clicking the Retry button, and being patient, will generally overcome this issue. Sometimes it may take a little longer for WCM to establish the connection to the Cintiq27QHD Look-Up Table (LUT).
Make sure you have rebooted your computer after installing the Wacom drivers. The driver installer will need to install a special file to make the WCM-Display LUT functional and it requires a reboot.
If you are still not having any luck, please try the following: Plug the WCM calibration hardware directly into the computer Plug the USB cable from the Cintiq27QHD directly into the computer. If already in the computer, swap out the USB 3.0 cable with the included USB 2.0 cable. Sometimes USB 3.0 cables can causes interference with other signals. This will usually clear this up