Summary
An upload usually fails because of a connection interruption, an unsupported video codec, or a file type that doesn't match what the question asks for.
If Something Goes Wrong
Symptom: You see an "Upload Failed" message.
Cause: Your internet connection was interrupted, you navigated away from the page during upload, your video uses an unsupported codec (common with iMovie's Apple ProRes/"Best" export), or the file type doesn't match what the question requires (for example, uploading audio to a question that needs video).
Fix:
- Try uploading the file again without navigating away from the page.
- If you exported the video from iMovie, re-export it with a custom, high-bitrate setting instead of Apple ProRes. See Troubleshooting: .MOV File Won't Upload (Mac) for the full steps.
- Double-check the file type matches what the question is asking for.