The issue has been resolved.
It looks like that some USB-ports does not deliver enough energy to initiate the loading process. My device was plugged in the night and today mornng it was still at 0%. Then I unplugged the cable from the computer and attached it via adapter to the socket and it began to load immediatly.
Now on another laptop, the charging process works fine and I can use the device.
Best regards,
Peter
