WD N900 C Remote Access ERROR server unknown error 500 Internal Server Error

could someone help me to find out the solution for this internal error?
I have tried to instal all the Firmware version but no result.
What am i doing wrong?

i’ll get this error message and it doesn’t want to turn on :((((

ERROR

server unknown error

500 Internal Server Error

my product is a WD N900C

any other ideas?
Please HELP!