When using a POP email account with iPhone or iPod touch, Mail will occasionally remove cached email messages from the following folders: Sent Drafts Trash Note: This only affects the local copies of messages stored on the device, it does not affect messages that are kept on the server.1

Visit link:
iPhone and iPod touch: About the purging feature for POP email accounts

Similar Posts:

• Supported push mail accounts on iPhone and iPod touch
• iPhone and iPod touch: Using a POP account with multiple devices
• iPhone and iPod touch: Search with Mail accounts and servers
• iPhone and iPod touch: Search with Mail accounts and servers
• iPhone and iPod touch: Gmail account will not connect to Gmail server