Inside the Cleaning Cap in your Toolkit, you will find an extra circular piece of Adhesive. Place the new Adhesive in the center of the current one and try again to install the Dock.
When installing the dock, be sure to clean and dry the surface you are adhering to. Once dry, press and hold the dock firmly against the desired mounting location for 20 seconds. After adhering the dock, wait 20 minutes before placing your wand on the dock or using your shower in order to give the adhesive time to cure.