When a user tries to connect a new dock, they can't use the monitors or keyboard/mouse.
Also, might get a warning from the Notebook "Device is Not Charging".
Is the Thunderbolt Connector Light on?
Unplug the Thunderbolt Connector from the Notebook.
Unplug the power from the dock, with a few seconds and plug the power back into the Dock.
Plug the Thunderbolt Connector into the Notebook.
If the light is not on, then unplug all cables/wires from Dock, wait 10 seconds, then plug in all peripherals and the power last. Now plug in the Thunderbolt connector into the Notebook.
If the light is not on, try Notebook on a different Dock. If it works on the new device, put in a ticket to replace the Dock.
They probably have not authorized the dock to Connect to the Device.
You get one chance to Authorize the Dock from the PC. If you miss this, then you will need to find the Thunderbolt Software and Authorize it.
Go to the the Thunderbolt Software in the Hidden Icons and right-click the Thunderbolt Icon and select Approve Attached Devices
If the icon is missing see, Support Article Thunderbolt Software Missing.
Select the correct port
Select Always Connect and OK