There are many files with the same format but different encoding methods. Even if your video format is supported, it may not be uploaded for use if the built-in encoding format is not supported.
For example, the MPEG4 encoding in MP4 format is not supported and needs to be transcoded before it can be used, but the H.264 encoding in the MP4 format is supported.
Normally, we automatically transcode unsupported video files. If unfortunately your video file can't be transcoded, we recommend that you change its format directly. There are some online converting tools available.