i use mediaPackage convert hls to dash, it failed, and i don't konw why it failed

Use a media player (like VLC) to directly play the HLS source and ensure it works. Use an HLS validator tool (there are online tools available) to check the integrity of your manifest files. and for more details Go to the AWS Elemental MediaPackage console. Locate the failed job within your channel. Check the detailed logs for specific error messages that can pinpoint the problem.