Sometime video buffering very slowly in exoplayer?

I don't know why, but sometimes Exoplayer buffers my video very slowly. My server is responding properly and the internet is also fast but sometimes Exoplayer buffers my video slowly for less than 1 second. And it buffering always after every 1-2 seconds on playing.

        int MIN_BUFFER_DURATION = 3000;
        int MAX_BUFFER_DURATION = 8000;
        int MIN_PLAYBACK_RESUME_BUFFER = 1500;
        int MIN_PLAYBACK_START_BUFFER = 500;
        LoadControl loadControl = new DefaultLoadControl.Builder()
                .setAllocator(new DefaultAllocator(true, 16))
                .setBufferDurationsMs(MIN_BUFFER_DURATION,
                        MAX_BUFFER_DURATION,
                        MIN_PLAYBACK_START_BUFFER,
                        MIN_PLAYBACK_RESUME_BUFFER)
                .setTargetBufferBytes(-1)
                .setPrioritizeTimeOverSizeThresholds(true).createDefaultLoadControl();
        TrackSelector trackSelector = new DefaultTrackSelector();
        simpleExoPlayer = new ExoPlayer.Builder(this).setTrackSelector(trackSelector).setLoadControl(loadControl).build();
        binding.exoPlayerView.setPlayer(simpleExoPlayer);
        mediaItem = MediaItem.fromUri(getVid);
        simpleExoPlayer.addMediaItem(mediaItem);
        simpleExoPlayer.prepare();
        simpleExoPlayer.play();

Does anyone know why this happens? Your answer will helpful for me.

from Sometime video buffering very slowly in exoplayer?