503 on TS-262 Owncloud V



i’m trying to install owncloud on my new QNAP TS-262.
After installing owncloud im greeted with:
503 Service Unavailable
The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.

Every setup tutorial is just displaying install and logon. Unfortunately i’m not that skilled with SSH or Telnet.

Do you have any idea what i’m doing wrong?`

Thanks in advance