- Press the Home button on your iOS device and choose Settings.2. Scroll down and click “Mail, Contacts, Calendars” from the list.
- Click your email account – it should have an arrow to the right of the email address displayed.
- Scroll to the end on the settings and click Advanced.
- Scroll down and tap the empty IMAP Path Prefix.
- Enter INBOX in capitals, then click ‘Accounts’ at the top left and click ‘Done’ at the top right twice to close the settings.
- Press the Home button and then re-open Mail.
You will now be able to delete or move your emails on your iOS device without the error message appearing.