If you are using Synapse 4, it will not tell you that your Dock Pro requires an update from firmware 1.xx to firmware 2.xx.
You've gotta manually download from their official website by searching on google for "Razer Mouse Dock Pro Firmware".
Once you have updated to firmware 2.xx, head over to Razer Synapse 4 to do the pairing process again. And this time it should pair and you should be able to move your mouse.
Enjoy your 8k polling.