mRxAudioPlayer.getMediaPlayer().pause() returning null

[qadirsuh]

I have started the audio recording. like

mAudioRecorder = AudioRecorder.getInstance();
        mAudioFile = new File(Utils.getTodayAudioDirectory() +
                File.separator + System.nanoTime() + ".file.m4a");

        Log.e("mAudioFile Path", mAudioFile.toString());

        mAudioRecorder.prepareRecord(MediaRecorder.AudioSource.MIC,
                MediaRecorder.OutputFormat.MPEG_4, MediaRecorder.AudioEncoder.AAC,
                mAudioFile);
        mAudioRecorder.startRecord();

Now I wanted to pause it

I tried like mRxAudioPlayer.getMediaPlayer().pause();

But I am getting null FATAL EXCEPTION: main Process: enact.employ.tracking, PID: 1017 java.lang.NullPointerException: Attempt to invoke virtual method 'void android.media.MediaPlayer.pause()' on a null object reference

I am testing on Marshmallow 6.0 device