Hey @chinyin818, thanks for reaching out to the Community!
Does this happen with one song or multiple? Can you try another thorough reinstall of the app following these steps? It's different from the simple reinstall you've done.
Also, you mentioned your iOS version is iOS 14.0.1. There's a new iOS update available for your iPhone. You can update by going to Settings > General > Software Update. Let me know if the issue continues after the update.
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