I uploaded a video almost a year ago.  When I search for it using the youtube app for iphone, it doesn't come up in the search results.  I'm only able to find it by watching another one of my videos and tapping the "more videos" button.

The video is set to be shared on mobile devices.  There are no copyright claims against it.  I can play it on my iphone but it doesn't come up when I search for it.  What is the problem and how can I fix it?