When sending files using creativehub the link you are using to share your files is only available for a limited amount of time. You can choose if the link expires after 7 days, 14 days or 21 days.
If you don’t make any changes to it the link will expire automatically after 7 days.
To change the expiry time for your link select the files you would like to send and click 'Send files’. In the overlay that opens up click on ‘Settings’ in the top right corner, here you can find the section ‘Expires after’ that allows you to choose for how many days the link will be available for.