   Serial.print("POST message: ");
   Serial.println(buffer2);
     
-  fona.HTTP_POST_start(url, F("Content-Type: application/json"), (uint8_t *)buffer2, strlen(buffer2), &statuscode, &response_length);
+  fona.HTTP_POST_start(url, F("application/json"), (uint8_t *)buffer2, strlen(buffer2), &statuscode, &response_length);
 
   Serial.print("Status: ");
   Serial.println(statuscode);

  // We need to wait the initialization in order to enable GPRS
  // So...
  delay(10000);
  if (!fona.enableGPRS(true))
  {
    Serial.println("FONA GPRS not enabled!");
  }
  
  if (!fona.enableNetworkTimeSync(true)) {

    len = strlen(buffer);
    buffer[len] = ';';
    len++;
    sprintf(&buffer[len], "E=");
    len = strlen(buffer);
    dtostrf(light_lvl, 1, 0, &buffer[len]);

