I guess AE is missing a codec for the embedded audio.
You have a MPEG video file, with m2ts file ending. I've never seen such and I doubt that this is any standard professional video codec.
So the best would be to transcode the video, or just extract the audio using Media Encoder.
I would extract the audio as first try. Put the video file into AME and convert it to WAV. Import the wav file to AE and check for sync. If everything went well, both layers should have the exact same length and lip movement should by in sync with audio.
To prevent any sync issues, you can also transcode the whole video file to a new format. I would use a high quality codec like DNxHD, ProRes or such. The result might be a very large file, but rather this than loosing quality.
If AME can't process the video, try another media encoder like Handbrake, MediaCoder, MPEGStreamclip (if this is still running) or even VLC.