In order experience, you are facing this problem because the Video files are not optimized for streaming.
Video MP3 files should be correctly encoded with H.264. Here is our suggestion on how to encode MP3 file correctly using VLC Media Player.
- Select the option: Covert/Save
- Select the profile: H.264 + MP3
- On the encapsulation tab, select MP4/MOV
- Keep original audio track box checked