Getting your export
The download link from Snapchat has expired. What do I do?
Ask for a new export the same way you did last time. The links expire, and reordering is fine and free.
Snapchat's download links expire: they stay up for a couple of days and then disappear. If yours has stopped working there is nothing to repair, and it is not something you did wrong. You simply ask for a new export in the app, exactly as you did the first time.
It costs nothing to reorder, and you can do it as many times as you need to. There is no penalty and no limit on requesting your own data, so an expired link is an inconvenience rather than a loss.
Take the opportunity to check three things before you send the new request, so you can avoid a third round: that Export your Memories is ticked, that Export JSON Files is ticked, and that you have moved out whatever you want to keep from My Eyes Only.
When the new link arrives, download the files while you have the email in front of you. If you have a large archive in several parts, tick them off as you go. It is easy to miss one out of seven, and a missing part is not obvious later: the archive simply comes out short, without anything looking broken.
One tip if your connection is poor: download the parts one at a time rather than in parallel. An interrupted download of a 2 GB file is annoying; four interrupted at once is worse. Check the size of each file when it lands, too. A part that weighs a few hundred bytes instead of hundreds of megabytes is an error message, not an export.