Why does my EBox Smart stop responding when I approach it and press a button?

My EBox Smart was put into operation and registered about 1 year ago. After that, it has always activated itself when approached and thus signaled charging readiness. A few months ago, however, the wallbox always remained dark when approached and could not be activated even by pressing a button. Unfortunately, our e-car arrived only a few days ago and now it would be time to charge. Can anyone tell me how I can wake up the box again from her "Sleeping Beauty", the usual measures such as fuses out / clean, the box from the EKlick out and back in brings at most a lighting up of the ring around the box in different colors, before the box obviously turns off again. There's nothing in the documentation, there's no thought of configuring it as I can't start bluetooth pairing etc. - the electrician company that registered the box with the electricity supplier will also only be mildly interested, as I bought the box from E.ON at the time, which in hindsight turned out not to be really helpful. Many thanks for tips on how to fix it.