Why do I get this error? volley.clientError

I find myself making a record and this error appears.

public class Registrarse extends AppCompatActivity {
    EditText identificacion,nombres,telefono,direccion,email,password;
    Button registrarse,iniciar;
    RequestQueue rq;
    String URL = "http://192.168.1.4:80/ServiciosBanco/clienteInsert.php";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_registrarse);

        identificacion = findViewById(R.id.etidentificacion);
        nombres = findViewById(R.id.etnombres);
        telefono = findViewById(R.id.ettelefono);
        direccion = findViewById(R.id.etdireccion);
        email = findViewById(R.id.etcorreoreg);
        password = findViewById(R.id.etpasswordreg);
        registrarse = findViewById(R.id.btnregistrarsereg);
        iniciar = findViewById(R.id.btniniciarreg);
        rq = Volley.newRequestQueue(Registrarse.this);

        iniciar.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent iniciar = new Intent(Registrarse.this,MainActivity.class);
                startActivity(iniciar);
                finish();//Cierra la actividad.
            }
        });
        registrarse.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                StringRequest request = new StringRequest(Request.Method.POST, URL, new Response.Listener<String>(){
                    @Override
                    public void onResponse(String s) {
                        Toast.makeText(Registrarse.this, "se ha registrado correctamente", Toast.LENGTH_LONG).show();
                    }
                },new Response.ErrorListener(){
                    @Override
                    public void onErrorResponse(VolleyError volleyError) {
                        Toast.makeText(Registrarse.this, "Ah ocurrido un error en: -> "+volleyError, Toast.LENGTH_LONG).show();
                    }
                }) {
                    @Override
                    protected Map<String, String> getParams() throws AuthFailureError {
                        Map<String, String> parameters = new HashMap<String, String>();
                        parameters.put("idcliente", identificacion.getText().toString());
                        parameters.put("nombres", nombres.getText().toString());
                        parameters.put("telefono", telefono.getText().toString());
                        parameters.put("direccion", direccion.getText().toString());
                        parameters.put("email", email.getText().toString());
                        parameters.put("password", password.getText().toString());
                        return parameters;
                    }
                };

                RequestQueue rQueue = Volley.newRequestQueue(Registrarse.this);
                rQueue.add(request);
            }
        });
    }
}