first be sure to add the permission to send SMSs
<uses-permission android:name="android.permission.SEND_SMS" />
and then surround your code with try and catch to find the error that prevents sending in Samsung s3 lte ..
try {
SmsManager smsManager = SmsManager.getDefault();
smsManager.sendTextMessage("01234567890", null, msg, sentPI, null);
Toast.makeText(getApplicationContext(), "SMS Sent!",
Toast.LENGTH_LONG).show();
} catch (Exception e) {
Toast.makeText(getApplicationContext(),
"SMS faild, please try again later!",
Toast.LENGTH_LONG).show();
e.printStackTrace();
}