Set up loop keeps looping (Adurino) - c++

Question

I am currently troubleshooting a code in Arduino for a temperature and humidity project. There is a line in the void setup(), Serial.println("Feather LoRa TX Test!");, which keeps popping up. My ideal code is to run that particular line once in the output and that will be it. However, the current code keeps repeating that line again, and again. May I know how do I rectify this issue (The whole code is below)? Thanks in advance!!
#include <RH_RF95.h>
#include <DHT.h>
#define DHTPIN 7 // what digital pin we're connected to
#define DHTTYPE DHT22 // DHT 11
DHT dht(DHTPIN, DHTTYPE);
#define RFM95_CS 10
#define RFM95_RST 9
#define RFM95_INT 3
// Change to 434.0 or other frequency, must match RX's freq!
#define RF95_FREQ 915.0
// Singleton instance of the radio driver
RH_RF95 rf95(RFM95_CS, RFM95_INT);
int node = 3; // to change based on node deployment
void setup()
{
pinMode(RFM95_RST, OUTPUT);
digitalWrite(RFM95_RST, HIGH);
while (!Serial);
Serial.begin(9600);
delay(100);
Serial.println("Feather LoRa TX Test!");
digitalWrite(RFM95_RST, LOW);
delay(100);
digitalWrite(RFM95_RST, HIGH);
delay(100);
while (!rf95.init()) {
Serial.println("LoRa radio init failed");
while (1);
}
Serial.println("LoRa radio init OK!");
// Defaults after init are 434.0MHz, modulation GFSK_Rb250Fd250, +13dbM
if (!rf95.setFrequency(RF95_FREQ)) {
Serial.println("setFrequency failed");
while (1);
}
Serial.print("Set Freq to: "); Serial.println(RF95_FREQ);
dht.begin();
rf95.setTxPower(23, false);
}
void loop()
{
float t = dht.readTemperature();
float h = dht.readHumidity();
if (isnan(h) || isnan(t)) {
Serial.println("Failed to read from DHT sensor!");
delay(1000);
return;
}
String d = "{\"Node\":"+ String (node) +",";
d += "\"Temp\":"+ String (t)+",";
d += "\"Hum\":"+ String (h);
d += "} "; // Add a trailing space is necessary
Serial.println("Transmitting...");
char data[d.length()];
d.toCharArray(data,d.length());
Serial.println(d);
rf95.send((uint8_t*)data, sizeof(data));
Serial.println("Waiting for packet to complete...");
delay(1000);
rf95.waitPacketSent();
Serial.println(" complete...");
delay(57000); // delay 1 minute
}

Answer 1

You have an infinite loop before you do any initialization. This will be detected because Arduino have a watchdog timer, and the system will reset.
And on reset setup is called again, and you again enter the infinite loop.
The loop it's about:
while (!Serial);
You must call Serial.begin(...) before that loop:
Serial.begin(9600);
while (!Serial);

Answer 2

Something is resetting your MCU before the code reaches the loop function. Therefore the setup function gets executed again and again. You can add more print messages in between lines so you'll know where it breaks.