Closed Unassigned: Unable to get Folders [2594]

Here is the debug output:
```

IMAPX1 CAPABILITY

* CAPABILITY IMAP4rev1 UIDPLUS CHILDREN ID XLIST NAMESPACE IDLE AUTH=PLAIN
IMAPX1 OK CAPABILITY completed.
IMAPX2 LOGIN "XXXXX" "YYYY"

IMAPX2 OK Success.
IMAPX3 XLIST "" %

* BYE Internal error.

```

Oddly enough; it does work for other accounts to the same server.

Any ideas?