There is a better way^^ Just activate it:
In your browser open the following urls one after another:
Replace the following: URL, PORT, USER, PASS, SERIALNUMBER (dont replace any other symbols like : oder ")
https://URL:PORT/webapi/auth.cgi?api=SYNO.API.Auth&method=Login&version=1&account=USER&passwd=PASS
https://URL:PORT/webapi/entry.cgi?api=SYNO.ActiveBackup.Activation&method=set&version=1&activated=true&serial_number="SERIALNUMBER"
To get the current activation status call the 1. query above and then
https://URL:PORT/webapi/entry.cgi?api=SYNO.ActiveBackup.Activation&method=get&version=1
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Example for
url: server,
port: 5001,
user: admin,
pass: admin,
serialnumber: 123400
link here: