We have add the search service application to our SharePoint 2013 farm.
The crawl log shows no errors and everything looks fine so far.
Now we are facing the problem that searching is possible via the search bar
at the top on our homepage and it also find items within all subsites, but
when I navigate to a subsite, doesn't matter which one, and use the search bar of
the specific site, it doesn't find any item within this site or outside. Also it doesn't find
any item located in a library even when I use the search bar at the top of the specific library.