When one does a search in FASO email for the first time, it gives an error message:

Your search results are currently unavailable. We can correct this automatically, if you wait just a little while and then try your search again.

You need to wait 24 hours after the first time you try to search and then the feature begins working.

We apologize for the inconvenience; according to our email provider Rackspace, it's just how it works (ie please don't shoot the messenger).