Error 0x800CCC0F on MS Outlook 2010

I am running MS Outlook 2010 on Windows 7 Final x64. From day to day I received this problem information: “Task '[email protected]' – Sending' reported error (0x800CCC0F): 'The message cannot be saved to your IMAP e-mail account Sent Items folder, because Outlook is offline or the e-mail server doesn’t allow items to be saved to the Sent Items folder.” What can be the cause of this error?
