Android : Android Send SMS Error

I'm trying to send an SMS in Android to a specific number and port, using the following code:

final String SENT = "SMS_SENT";
PendingIntent sent = PendingIntent.getBroadcast(context, 0, new Intent(SENT), 0);

registerReceiver(Globals.smsReceiver, new IntentFilter(code));

SmsManager manager = SmsManager.getDefault();
manager.sendDataMessage(Globals.NUMBER, null, Globals.PORT, message.getBytes(), sent, null);

Globals.smsReceiver is a "SMSSentBroadcastReceiver" object, which is a subclass of "BroadcastReceiver". Globals.PORT is 5000.

However, when the code reaches onReceive() on SMSSentBroadcastReceiver, it receives a RESULT_ERROR_GENERIC_FAILURE code. According to the documentation, I checked for the "errorCode" in the sentIntent and it returned 42. What does this mean? What is happening and how can I send an SMS?

Also, this code worked before. It stopped working for no apparent reason, except for the fact that I changed the SIM Card on the mobile to a different number. But I checked that this card is enabled and can send "normal" SMS through the default SMS app.

Finally, my Manifest also has this:

<uses-permission android:name="android.permission.SEND_SMS" />
<uses-permission android:name="android.permission.RECEIVE_SMS" />

And this:

<receiver android:name=".support.SMSSentBroadcastReceiver" >
      <intent-filter>
            <action android:name="SMS_SENT" />
      </intent-filter>
</receiver>

How can I figure out what "42" errorCode is and what I can do about it?

Thanks in advance!