You are getting this error.

Error Sorry, the requested download has expired

When you use the link in the email?

Under admin->tools->Download Fetch File
Select the file that you wish to change and edit the Active Period to a value that you want.
ie.
86400 = 1 day
604800 = 1 week
2419200 = 1 month
29030400 = 1 year

If you just want to allow one user/customer more time then you must go to Download Fetch User Admin and adjust the download date.

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