Every file is open for download for 48 hours because of contractual reasons. After 48 hours, the download will close. If you need to re-download your track, please submit a request and our support team will re-authorize as a one time courtesy. Make sure to include the song you need to have reauthorized and the email address associated with your account.
If you ever need to re-download content after the one-time re-authoriazation, we suggest looking into a MultiTracks Cloud subscription.