SSLHandshakeException on WebSocket connection with OkHttp3

Question

I'm trying to connect to WSS websocket using OkHttp3, but I got in onFailure() method of my WebSocketListener in particular the Exception said:

javax.net.ssl.SSLHandshakeException: Handshake failed

Now, I'm using this code to connect to WSS

OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder().url("wss://mywssdomain").build();
WebSocketListenerCP listener = new WebSocketListenerCP(); //My listener, do nothing only override methods
WebSocket ws = client.newWebSocket(request, listener);
client.dispatcher().executorService().shutdown();

I've read a lot about issue with Android < Lollipop but I'm on Nougat anyway I've tried to nuke all SSL certificate by doing (before connection)

SSLCertificateHandler.nuke();

SSLCertificateHandler class

import java.security.SecureRandom;
import java.security.cert.X509Certificate;

import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSession;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;

public class SSLCertificateHandler {

    /**
     * Enables https connections
     */
    public static void nuke() {
        try {
            TrustManager[] trustAllCerts = new TrustManager[] { new X509TrustManager() {
                public X509Certificate[] getAcceptedIssuers() {
                    X509Certificate[] myTrustedAnchors = new X509Certificate[0];
                    return myTrustedAnchors;
                }

                @Override
                public void checkClientTrusted(X509Certificate[] certs, String authType) {
                }

                @Override
                public void checkServerTrusted(X509Certificate[] certs, String authType) {
                }
            } };

            SSLContext sc = SSLContext.getInstance("SSL");
            sc.init(null, trustAllCerts, new SecureRandom());
            HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());
            HttpsURLConnection.setDefaultHostnameVerifier(new HostnameVerifier() {
                @Override
                public boolean verify(String arg0, SSLSession arg1) {
                    return true;
                }
            });
        } catch (Exception e) {
        }
    }
}

And I also tried to add connectionSpecs to my OkHttp3 client

ConnectionSpec spec = new ConnectionSpec.Builder(ConnectionSpec.MODERN_TLS)
        .tlsVersions(TlsVersion.TLS_1_2)
        .cipherSuites(
                CipherSuite.TLS_DHE_DSS_WITH_AES_128_CBC_SHA,
                CipherSuite.TLS_DHE_RSA_WITH_AES_256_CBC_SHA)
        .build();

OkHttpClient client = new OkHttpClient.Builder().connectionSpecs(Collections.singletonList(spec)).build();
Request request = new Request.Builder().url("wss://mywssdomain").build();
WebSocketListenerCP listener = new WebSocketListenerCP();
WebSocket ws = client.newWebSocket(request, listener);
client.dispatcher().executorService().shutdown();

I'm not understand

1) Why I get SSLHandshakeException?

2) Is right connection to WSS?