By default, every digital download link will expire after 24 hours. This is designed to stop customers from sharing your links or even posting them publicly.
You can change this 24-hour deadline by going to Downloads » Settings in your WordPress dashboard. You can then head over to Misc » File Downloads.
Now, you’ll want to find the ‘Download Link Expiration’ field. Then, simply type in the number of hours you’d like the download link to be available before it expires.