Before trying advanced methods, ensure the problem isn't a simple browser or setting conflict.
| Error Message | Root Cause | Fix Priority | | :--- | :--- | :--- | | "Failed to fetch playlist" | YouTube changed the playlist JSON structure. The plugin cannot find the video list. | High | | "Unable to extract signature" | YouTube updated the cipher algorithm. The plugin cannot decrypt the video URL. | Critical | | "429 Too Many Requests" | You (or the plugin) triggered YouTube’s rate limiting. Your IP is temporarily blocked. | Medium | | "Downloaded 1 of 50 videos" | The plugin’s loop iterator broke after the first result. Usually a DOM selection bug. | High | | "Plugin not responding" | Memory leak or infinite loop. The page’s JavaScript conflicts with the plugin. | Medium | | “This plugin has been disabled for your protection” | Mozilla removed it from addons.mozilla.org due to policy violations or malware. | Severe | youtube playlist downloader firefox plugin fix
If you want, I can: