If things sit connecting for a long time & then need more sources, could be fake files. You see this most often with files that have lots of sources.

If the file's not a fake, it could be that the source has gone offline since you searched or that they've got no upload slots free for you to download that file. In that case, try downloading a different file or search again. People are constantly shutting down & new people coming online, so a new search might bring up different results.