My N900 looks for new E-Mails every 30 minutes. However, if my mail server does not answer in time, the mail client hangs on this mail account and I can neither look into already received messages (the folder "Inbox" just isn't there) nor can I receive any new mails. The only folders I see are "Drafts", "Outbox" and "Sent". I also see some kind of circle showing me that it is loading something - however, it doesn't go away! Pressing the button for receiving new mail again doesn't help.

I can only fix that by restarting the device :-/
Any ideas on this?