Not receiving TXT messages via T-mobile, works with AT&T

[alano]

I’m testing a pretty simple sketch using the MKR 1400. This sketch receives txt messages and then echos them via a socket connection.

#include <MKRGSM.h>
const char PINNUMBER[] = " ";
const char GPRS_APN[] = "hologram";
const char GPRS_LOGIN[] = " ";
const char GPRS_PASSWORD[] = " ";

String HOLOGRAM_DEVICE_KEY = "********";
String HOLOGRAM_TOPIC = "_SOCKETAPI_";

GSMClient client;
GPRS gprs;
GSM gsm(1);                                             // Enable debug
GSM_SMS sms;
GSMScanner scan;

char server[] = "cloudsocket.hologram.io";
int port = 9999;
boolean isSMSAvailable = false;
char sms_message[145];

void setup() {
  Serial.begin(115200);
  while(!Serial);

  scan.begin();
  connectGSM();
     
}

void connectGSM() {
  boolean connected = false;

  while (!connected) {
    Serial.println("Begin GSM Access");
      
    if ((gsm.begin() == GSM_READY) &&
        (gprs.attachGPRS(GPRS_APN, GPRS_LOGIN, GPRS_PASSWORD) == GPRS_READY)) {
      connected = true;
      Serial.println("GSM Access Success");
      Serial.println(scan.getCurrentCarrier());
    } 
    else {
      Serial.println("Not connected");
      delay(1000);
    }
  }
}

void loop() {
  static bool enableSMS = true;

  if(Serial.available()) {
    char c = Serial.read();
    if(c == 'e')
      enableSMS = true;
    if(c == 'd')
      enableSMS = false;
  }
  
  // Get any new incoming txt messages
  int c;
  if (enableSMS && sms.available()) {
    int i = 0;
    while ((c = sms.read()) != -1) {
      sms_message[i++] = (char)c;
    }
    sms_message[i] = '\0';        // Terminate message
    isSMSAvailable = true;
    sms.flush();
  }

  if(gsm.isAccessAlive()) {
    if(gprs.status() != GPRS_READY) {
      if(gprs.attachGPRS(GPRS_APN, GPRS_LOGIN, GPRS_PASSWORD) == GPRS_READY)
        Serial.println("GPRS ready!");
      else
        Serial.println("GRPS not ready!");
      Serial.println("THIS NEVER GETS CALLED!");
    }
  }
  else {
    Serial.println("Reconnect to GSM...");
    connectGSM();
  }

  // Send message back through hologram
  if(isSMSAvailable) {
    isSMSAvailable = false;

//    delay(1000);
    if (client.connect(server, port)) {
      client.print("{\"k\":\"" + HOLOGRAM_DEVICE_KEY + "\",\"d\":\"");
      client.print(sms_message);
      client.println("\",\"t\":\""+HOLOGRAM_TOPIC+"\"}");
      client.stop();
    }
  }

  delay(5000);
}

Any ideas why this would work when I’m connected to AT&T and stop working when I’m connected to T-Moble. The debug log is shown below:

OK
AT+CMGL="REC UNREAD"

OK
AT+CREG?

+CREG: 0,5

OK
AT+CMGL="REC UNREAD"

OK
AT+CREG?

+CREG: 0,5

Any help would be appreciated.

[alano]

After an hour or so, I’m now receiving txt messages via T-Mobile. Doesn’t give me a lot of confidence in their network though.