Can't import mp3 sound with existing single frame

I am now having this problem too I tried to re-import the audio but it said that there was already audio on the one frame. The audio was originally .mp3 and then I converted it to .wav and it still did not work in the program but I could open it and use run it. The audio still sounds fine and runs nicely.
Audio length:25 seconds
Program version:Version: 0.6.3
Operating System: Windows 10 (10.0)
CPU Architecture: x86_64

Your issue is very likely the same issue with the encoding of your .mp3 file. Pencil2D does not allow you to have two sound files on the same layer and frame, so you must delete your old sound attempt before you can import the new one on the same spot. This is done with the delete frame button in the timeline.

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