During the usual descaling process, the pump sucks in the water/descaling agent, pauses for it to take effect and then continues pumping. My machine sucked in the water and then nothing went through. The pump tries to transport the water but this no longer works. When I switch the machine off and on again, it is always in "descaling mode". This means I have no chance of priming the pump again. What can I do now? How can I deactivate this mode?