Generated document link not active for 30 days

I am using the Generate Document feature and sending a document via Smartsheet; when I open the Send Attachment information box to fill in, it has a note that the link to download the file is active for 30 days and will be included in the message. I sent a document yesterday and the recipient emailed me this morning as the link was only active for the day I sent it, not 30 days. Any idea what to do as I will be using this feature several times a week and know that the recipient's won't necessarily open the document the same day.

tested it again this morning and this is in the email - this is not 30 days:

File links in this email will be active until July 29, 2023