API login request -> errorCode 551

Hello,
i try to connect to the API ping and application works, but when I try to login, I get the errorCode 551
The documentation say: 551= missing Authorization header , but I send it.
Here is the Header I'm sending:
[Accept] => application/json
[Authorization] => Serviio aOVyTJUIV5jqIiut9SdDaHkXCuM=
[Date] => Sat, 25 Oct 2014 15:42:45 GMT+00:00
[X-Serviio-Date] => Sat, 25 Oct 2014 15:42:45 GMT+00:00
[Content-Length] => 0
[Host] => 192.168.188.26
[Connection] => Keep-Alive
The Log File says:
i try to connect to the API ping and application works, but when I try to login, I get the errorCode 551
The documentation say: 551= missing Authorization header , but I send it.
Here is the Header I'm sending:
[Accept] => application/json
[Authorization] => Serviio aOVyTJUIV5jqIiut9SdDaHkXCuM=
[Date] => Sat, 25 Oct 2014 15:42:45 GMT+00:00
[X-Serviio-Date] => Sat, 25 Oct 2014 15:42:45 GMT+00:00
[Content-Length] => 0
[Host] => 192.168.188.26
[Connection] => Keep-Alive
The Log File says:
2014-10-25 17:43:57,792 WARN [ServiioStatusService] AuthenticationException occured. Returning error code 401 to the REST layer. Message: Value of Auth header from authentication request is invalid.