Is mail.hover.com set up as IMAP or POP3?
POP3 does not provide access to server folders, it only "sees" the Inbox.
Please long press on the account on the app's main screen -> options and folders
Will you see "POP3 Options" or "IMAP Options"?
If POP3 - try removing the account from the app and add it back, using the Manual button on the account setup screen and making sure to use IMAP.
If IMAP - tap into Folders and wait a bit for a refresh. Will it work?
If not, please capture this (options and folders -> folders with enough time to refresh) in the app's debug log (with "raw session data" enabled) and send us the log file. Please see my signature just below for a link to instructions about debug logging.