[BUG] Downloaded mp4 video will not play

[kokopoko30]

Describe the bug
Video downloaded in mp4 format can not be opened by mp4 player

To Reproduce
Steps to reproduce the behavior:
Use this to download video from teachable.

Expected behavior
The video file is able to be played by mp4 player as file is in mp4 format.

Desktop (please complete the following information):

• OS: Ventura 13.5.2
• Browser Version Chrome Version 120.0.6099.199 (Official Build) (x86_64)

[J-W-Smith]

I'm having the same issues, I noticed an error with ffmpeg, that it can't be found. I've redownloaded ffmpeg and set it for the environment, placed it in and tried doing the --ffmpeg-location, but it's not seeing it. I wonder if that's the issue.
I can play the videos in MPC but not in VLC for some reason as well.