There is a common error that may occur while loading your attachments. When you open a link it may fail to load displaying the following error:
This happens because the S3 attachment link becomes invalid within 12 hours if left open in a window and this causes the error. After 12 hours, the old attachment link expires and a new one is generated. To avoid the error, open your attachment again after 12 hours to continue viewing your attachment with the new link.