Code for the DS3231 suddenly stopped working

Hi.....

today i want to rebuilt my little alarmclock and it worked for around three Weeks at home. So i build it up in my new living room and uploaded my code and this piece of sh... stopped working..

It seems that i cant setup the time in the DS3231 or that it cant store the Data... I have tried a new Battery and lots of other code.

And i noticed that Arduino was updatet right? Because under Processors i have a new Point: ATmega328 "Old Bootloader".

Is it possible that this is the reason for my Problem?

Here is my Code:

#include <LiquidCrystal_I2C.h>
#include <Wire.h>
#include <DS3231.h>
#include <Keypad.h>


LiquidCrystal_I2C lcd(0x27,16,2); //0x27 eig standartadresse  oder 0x3F
DS3231 clock;
RTCDateTime dt;

String Alarmzeit = "sjadn";
String Aktzeit;

int LED = 3;
int SUMMER = 2;
int LICHTSENSOR = 4;

//Nochmal genau nachvollziehen! https://www.youtube.com/watch?v=GyprsoB887Y

const byte rows = 4;
const byte cols = 4;

char keys [rows][cols] = {
{'1','2','3','A'},
{'4','5','6','B'},
{'7','8','9','C'},
{'*','0','#','D'}
};

byte rowPins[rows] = {12,11,10,9};
byte colPins[cols] = {8,7,6,5};

Keypad keypad = Keypad(makeKeymap(keys),rowPins,colPins,rows,cols);



void setup(){
    Serial.begin(9600);
    clock.begin();
    
    lcd.begin();
    

    pinMode(LED,OUTPUT);
    pinMode(SUMMER,OUTPUT);
    pinMode(LICHTSENSOR,INPUT_PULLUP);
    
  //clock.setDateTime(2016, 12, 9, 11, 46, 00);
  clock.setDateTime(__DATE__, __TIME__);
}

void loop(){
  
Aktzeit = Zeitaktualisierung();  
Zeitausgabe();
Alarm();

//Menue
  
      char key = keypad.getKey();

      if(key == 'A'){

        lcd.backlight();
        lcd.display();
        
        lcd.clear();
        lcd.setCursor(0,0);
        lcd.print("Alarmeinstellung:");
        lcd.setCursor(4,1);
        lcd.print(Alarmzeit);
        
        lcd.setCursor(4,1);
        lcd.blink();

        char Stunde1 = keypad.waitForKey();
        lcd.print(Stunde1);
        String Stunde1Str;
        Stunde1Str = Stunde1;

        char Stunde2 = keypad.waitForKey();
        lcd.print(Stunde2);
        String Stunde2Str;
        Stunde2Str = Stunde2;

        lcd.setCursor(7,1);

        char Minute1 = keypad.waitForKey();
        lcd.print(Minute1);
        String Minute1Str;
        Minute1Str = Minute1;

        char Minute2 = keypad.waitForKey();
        lcd.print(Minute2);
        String Minute2Str;
        Minute2Str = Minute2;

        lcd.blink();

        delay(1000);
        lcd.clear();
        delay(1000);

        String Alarmzeit_Menue = Stunde1Str + Stunde2Str + ":" + Minute1Str + Minute2Str +":00    ";

        Alarmzeit = Alarmzeit_Menue;
        
        lcd.print("Neuer Alarm um:");
        
        lcd.setCursor(4,1);
        lcd.print(Alarmzeit);

        delay(5000);

        lcd.clear();

          int i=1;

        while(i<9){
              Aktzeit = Zeitaktualisierung();  
              Zeitausgabe();
              i++;
              }
      
      }
     
      
  if(key == 'B'){
      
        
        lcd.backlight();
        lcd.display();

        int i;
        
        while(i<9){
              Aktzeit = Zeitaktualisierung();  
              Zeitausgabe();
              i++;
              }
      
        }
  

      lcd.clear();
      lcd.noBacklight();
      lcd.noDisplay();
}
  
String Zeitaktualisierung(){

    dt = clock.getDateTime();

    String Aktzeit = clock.dateFormat("H:i:s    ",dt);

    return Aktzeit;
}


void Zeitausgabe(){
    Serial.println(Aktzeit);
    Serial.println(Alarmzeit);
  
    lcd.setCursor(4,0);
    lcd.println(Aktzeit);
    lcd.setCursor(4,1);
    lcd.println(Alarmzeit);
    delay(750);
    //lcd.clear();  
}

void Alarm(){
   if (Aktzeit == Alarmzeit){
        lcd.backlight();
        lcd.display();
        lcd.setCursor(3,0);
        lcd.print("Aufstehen");
        lcd.setCursor(4,1);
        lcd.print(Alarmzeit);
  
        
      
      while(digitalRead(LICHTSENSOR)==HIGH){
        digitalWrite(LED,HIGH);
        delay(1000);
        digitalWrite(LED,LOW);
        delay(1000);
        digitalWrite(SUMMER,HIGH);
        delay(300);
      }
      digitalWrite(SUMMER,LOW);
      lcd.clear();
    }
}

Maybe my Clock modul is broken?

I cant find the mistake....

Thanks for your help!

It seems that i cant setup the time in the DS3231 or that it cant store the Data... I have tried a new Battery and lots of other code.

That does no thelp describe what you see, what is the problem?how are things wired, powered?which arduino?...what code did you try?