This error usually occurs if a download link that has expired is used. By default, download links generated through our system expire after 60 days for security reasons. There are two ways to resolve this situation:
We can increase the 60 day period for your account to any period you desire.
You can issue another download link through our API, with the same order id and resource id.
Another reason for this can be incorrectly set time on your servers. Please ensure your servers are synced with world clocks with a mechanism such as NTP.