You may have received a download error for many reasons, some being our fault, some being yours. For example, there are certain audio and video format combinations that simply do not work together, and/or with the output merge format you selected. If this happens, just try a different combination, and perhaps research if your desired combination/setting is allowed by youtube-dl. Further, downloading some large files may fail, we are currently investigating this issue.

Many! Just try the video URL. See here for a full list.

Up to 24 hours.

We use youtube-dl behind the scenes. A lot of issues with this service directly stem from issues with youtube-dl.