Looking at the HTML, there is only one level's worth of list items in the navigation, no sub-items. So the navigation simply has no sub-menu items to display.

You'll need to make sure your Auto-Nav block is configured to show/output all the items that you want on your menu. You may have just got it set to show the first level of items, the default behaviour.

Change in the settings of the Auto-Nav block, both the 'Sub Pages to Display' and 'Sub-Page Levels' drop downs to Display All.