If you can effectively send email and view any new messages in your Inbox, however aren't ready to see extra subfolders, at that point almost certainly, you have an incorrect IMAP Path Prefix setting on the device.
To address this, take the following steps:
1. Go to Settings > Mail > Accounts > Select your email address > Account > Advanced
2. At the base of this screen, you should see 'IMAP Path Prefix'. Leave this clear or, have a go at entering 'INBOX'
3. Save the changes, and afterward explore back through the Email Account settings pages sparing as required
You'll currently have the capacity to see all folders in the account. If that doesn't help or it is now set up that way, you may need to remove and re-include the email account your device.
