The sound file does not loop

Hi Community,

I have got a problem that my sound file can't loop! I tried decreasing the bitrate, which does not work.

Help somebody could help me! Thank you very much!!!!

Here is my main tab! My classes are too long and maybe not related to the sound loop problem.So i did not include them.If the main tab does not have any question,i will go to check my classes.

import g4p_controls.*;
PImage back;

import processing.sound.*; 
SoundFile BGM;


void setup() {
  size(1800, 1000);
  back= loadImage("background13.png");
  textAlign(CENTER, CENTER);
  imageMode(CENTER);
  iniTial();
  createGUI();
  BGM = new SoundFile (this,"BGM.mp3"); 
  BGM.loop();
}


void draw() {
  background(255, 255, 255);
  drawBackground();
  keepersActivity();
  ballActivity();
  winSign();
  chaser_gryffindoActivity();
  chaser_slytherinActivity();

}