Sinch java error - sinch

Question

i am using sinch from java, i recently reput credit to the account, and now when i try to send message i get succes message, but the sms isn't send. Following the link https://messagingapi.sinch.com/v1/sms/162393899 i get this
{"errorCode":40107,"message":"Invalid authorization key:
vivi******#gmail.com","reference":"BA:vivi******#gmail.com_GtIfKPDMJEKL4VJWR0kkJQ"}
the code
try {
String phoneNumber = "+40732******";
String appKey = "*****";
String appSecret = "****";
String message = "Test";
URL url = new URL("https://messagingapi.sinch.com/v1/sms/" + phoneNumber);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setDoOutput(true);
connection.setRequestMethod("POST");
connection.setRequestProperty("Content-Type", "application/json");
String userCredentials = "application\\" + appKey + ":" + appSecret;
byte[] encoded = Base64.encodeBase64(userCredentials.getBytes());
String basicAuth = "Basic " + new String(encoded);
connection.setRequestProperty("Authorization", basicAuth);
String postData = "{\"Message\":\"" + message + "\"}";
OutputStream os = connection.getOutputStream();
os.write(postData.getBytes());
StringBuilder response = new StringBuilder();
BufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream()));
String line;
while ( (line = br.readLine()) != null)
response.append(line);
br.close();
os.close();
System.out.println(response.toString());
} catch (IOException e) {
e.printStackTrace();
}