Hey, @aria.zhenzhenli, welcome to the community forums, and thanks for posting your question here!
If you just started using your Misty, you may need to apply the Android patch that we released earlier this year. This patch fixes an audio recording bug that matches exactly the behavior you’ve described. You can find a link to download the patch and installation instructions here: 2020.01.07: Misty II Android Patch for Improved SLAM Performance
If you’ve already applied the patch and are still seeing this issue, let us know, and we’ll keep digging for the root cause
If you have questions about applying the patch or developing for Misty, please feel free to post them here!