Outlook 2007 'Your Out of Office settings cannot be displayed, because the server is currently unavailable. Try again later"

After an transition to SBS 2008, Outlook 2007 clients might get this warning when they try to open their Out Of Office Assistant.

You might also see this symptom below if you "Test E-Mail Autoconfiguration." in outlook.

Most troubleshooting websites point you to the certificate being incorrect. However the SBS wizard should have done the job correctly. I fixed this but disabling 'Require SSL' on the autodiscover virtual directory. If that does not work try the EWS virtual directory.