While downloading Facebook videos online is straightforward, users occasionally encounter errors like 0 KB audio files, private video blocks, or missing download buttons. These issues almost always stem from audience privacy settings or malformed redirect links.

If a video fails to download, check whether the post is set to "Public" (globe icon). If the video is inside a closed group or an audience-restricted Story, use FDownloader’s Page Source (Ctrl+U) mode to extract the direct authorized stream link.