The Ceramic Valve may not have been able to initialize. This valve distributes water to the hot water pipe, coffee dispenser and steam pipe. Over time, the valve becomes clogged with scale, therefore, it cannot switch between the aforementioned functions.
Replace Ceramic Valve.
Some Jura models have a Reactive Cable in the rear of the machine. This sensor is used for measuring the scaling degree (Tolerance).
Clean the contact pins, dry them and apply contact spray, if necessary.