I use Outlook 2011 (14.4.3) to connect to my organization's Exchange server from my Mac (OS 10.9). Normally I receive mail shortly after it was sent, but on occasion Outlook will refuse to check my mail for periods ranging from minutes to hours.

By "refuse to check my mail" I mean that:
    •    No new mail comes in, even if I know new messages are waiting
    •    When I click the "send/receive" button, the button responds with a click animation, but it does not check my mail.
    •    If I open the "progress" window (cmd-7) I can confirm that no activity is shown.

    •    No error window appears and no new messages appear in the "errors" window (cmd-8).

During these times:
    •    I can log in to webmail and confirm that there are messages that haven't been downloaded.
    •    My mac has full connectivity otherwise
    •    Outlook is able to send emails, which are received by others right away (but my sent mail box isn't updated either).

    •    The application functions normally otherwise, e.g., I can read and search old emails without any errors or lagging.

    •    The status message in the lower-right still says "connected to [account name]" and accurately displays the last time it connected to the server.

The problem sometimes resolves spontaneously, and I'll get a bunch of old mail at once.

Quitting and restarting usually fixes the problem. But that requires me to notice that it's happening, which sometimes doesn't happen for several hours, during which I can miss emails that required an immediate response.

Can anyone offer any suggestions or diagnostic steps?