System rebooting since yesterday!

the PR4100 is my very first NAS, so I am not familiar with problem issues. So far the first steps went fine, but since yesterday nothing works at all. The device only gives the notice “Sytem rebooting”, the start button is blinking blue. What can I do? Is my data lost?
Thanks for helping,


Thank you for choosing the WD PR4100 and reporting this issue

The data on the physical drive should not be harmed.
Please press and hold the power button to power off the unit.
Once powered OFF, press the button to power it back on.