UICollectionView can't scroll down

Question

i have uicollectionview in a view controller. i have HomeCell it's UICollectionViewCell and my UIView Controller is HomeController, but when i run my apps, the collection view cell doesn't scroll.

can you help me, im a new in using Objective-C language.

here's my HomeController.h code :

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
return arrayOfLyrics.count;
}


- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    Lyrics *lyric = [[Lyrics alloc]init];
    lyric = [arrayOfLyrics objectAtIndex:indexPath.row];


    CellHome *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"CellHome" forIndexPath:indexPath];
    cell.myTitle.text = lyric.title;
    cell.myArtis.text = lyric.artis;
    [cell.myImage setImage:[UIImage imageNamed:lyric.image]];

    return cell;
}

- (void)collectionView:(UICollectionView *)collectionView
didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
    _passLyric = [arrayOfLyrics objectAtIndex:indexPath.row];
    [self performSegueWithIdentifier:@"DetailView" sender:self];
}