Deleted Emails Still Appearing

Issue/Question

I have messages appearing that no longer exist in my account.

Cause

The iOS device has cached the messages locally and did not process their removal from the server.

Resolution

1. Open Settings .
2. Tap Passwords & Accounts.
3. Tap the account experiencing issues.
4. Tap the slider for Mail to disable syncing.
5. Tap the slider again to re-enable syncing.
6. Return to the Mail  app. Only the messages stored on the server will appear.