Sometimes, when a red cross appears in the Encoding column of the Uploader window, you simply need to close the window, reopen it and you'll see that the encoding is in fact still in progress.
If you've checked this and are sure that the encoding of the video has failed, here are the possible reasons:
- The video format is not supported (see Video Formats).
- There is a temporary issue due to a congestion of the flow, please try again later.
- The video is corrupted. Try re-exporting the video file via your editing software.
- If none of the above works, please ask your video support.