Interruptions do not work in certain situations

Hello,
I cannot figure out why the program hangs on the interrupt service routine. I tried to create an external interrupt and all was fine, than, I tried to create another interrupt, but this time after the execution of the interrupt service routine nothing happens, as if the program counter gets stuck there. Idk why.

#define zece_secunde 6000
#define trei_secunde 3000
#define exceptie 2000
#define minut 15000

void setup() {

  pinMode(LED_BUILTIN,OUTPUT);
  digitalWrite(LED_BUILTIN,HIGH);
  //inputs:
  pinMode(A0,INPUT_PULLUP);
  pinMode(A1,INPUT_PULLUP);
  pinMode(A2,INPUT_PULLUP);
  pinMode(A3,INPUT_PULLUP);
  //outputs:
  pinMode(A4,OUTPUT);
  pinMode(A5,OUTPUT);
  pinMode(A6,OUTPUT);
  //exceptions:
  pinMode(A7,OUTPUT);
  pinMode(A8,OUTPUT);
  //interrupts:
  attachInterrupt(A2, isr2, LOW);
  //test leds:
  digitalWrite(A4,HIGH);
  digitalWrite(A5,HIGH);
  digitalWrite(A6,HIGH);
  digitalWrite(A7,HIGH);
  digitalWrite(A8,HIGH);
  delay(1000);
  digitalWrite(A4,LOW);
  digitalWrite(A5,LOW);
  digitalWrite(A6,LOW);
  digitalWrite(A7,LOW);
  digitalWrite(A8,LOW);
  //automaton:
  start:
  if(digitalRead(A0) == 0){
    if(digitalRead(A1)){
      digitalWrite(A4,HIGH);
      delay(minut);
      digitalWrite(A6,HIGH);
      digitalWrite(A5,HIGH);
      before_wait_3sec:
      delay(trei_secunde);
      if(digitalRead(A3) == 0){
        digitalWrite(A6,LOW);//stop scanteie
        if(digitalRead(A1)){
          goto before_wait_3sec;
        } else {
          digitalWrite(A5,LOW);
          digitalWrite(A4,LOW);
          goto before_wait_1min;
        }
      } else{
        //exceptie2
        digitalWrite(A4,LOW);
        digitalWrite(A5,LOW);
        digitalWrite(A6,LOW);
        digitalWrite(A8,HIGH);
        delay(exceptie);
        digitalWrite(A8,LOW);
        goto start;
      }
    } else {
      before_wait_1min:
      delay(minut);
      goto start;
    }
  } else {
    delay(zece_secunde);
    goto start;
  }
}

void loop() {

}

void isr2(){
  digitalWrite(A5,LOW);
  digitalWrite(A4,LOW);
  digitalWrite(A6,LOW);
  digitalWrite(A7,HIGH);
}

Which Arduino board are you using ?

I don’t know any Arduino type that would execute that line correctly.

I see also no change to HIGH on A2, so the ISR would be called back to back,
probably single stepping the main code.

Arduino DUE

Arduino DUE does, I tried it. It does not function properly only within this excerpt of code, idk why, I suppose it may be something related to the goto label instructions.

Whether or not the gotos are causing a problem I strongly suggest that you get rid of them. They are not needed with properly structured code

You are not using attachInterrupt correctly. Check the documentation