Messages automatically expire after a period of time, usually 30 days. The message expiration date displays in the details of each email message you receive. If you want to keep a copy of the message after its expiration date, you can print it, save the message as a text file or save the message and any attachments as a .zip file.
You
can change the standard expiration for a message you are sending to a shorter period using the
Days to hold drop-down field
If you send a message and it expires, the message is removed from the recipient's Inbox and you are sent an email notification in your regular email Inbox with the following information:
You can then resend the message, if needed.