Be sure you are using your full email address for the user name when you log in. This mistake is much more common than you think. In Outlook, this is found at Tools > Accounts > Edit the email account > More Settings > Advanced > check box for Leave a copy of messages on the server. To prevent this from happening, be sure to set your POP3 account to leave copies of messages on your server.

POP Access UsedĪ POP3 configuration means your email will be stored locally in the email application you're using to access your mail on your computer or mobile device instead of an IMAP configuration where your emails are stored on the server. If you've set up multiple email applications (such as Outlook or Mail), your emails may have been downloaded to one of your other devices.

Check your other folders, especially Spam and Trash. It's possible that someone logged in and deleted or moved your emails or that your email filters have moved them. There are several possibilities as to why your emails seem to have suddenly disappeared:

My gmail inbox mail disappeared