Error with socket tcp on android

Question

I’m having a null error, I no longer know what I do, I’m using socket tcp in java in android studio, I already got the permission in the manifest, before I gave wrong permission denied, now the null error, and like I made this same code only using terminal, and it worked, only with the android studio q of the wrong

the code is this one

tn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Socket client;
            try {
                client = new Socket("10.0.1.138", 2000);
                while (true) {
                    Toast.makeText(getApplicationContext(), "Enviado para 10.0.1.138", Toast.LENGTH_LONG).show();
                    client.close();
                }
            }catch (Exception e){
                Toast.makeText(getApplicationContext(), "Ocorreu um erro:" + e.getMessage(), Toast.LENGTH_LONG).show();
            }

        }
    });