It should always work.
It seems to work very consistently for me. There are options of searching only certain areas and/or searching only the titles of posts. Maybe you had something selected that narrowed your search down too much? Were you using the overall search, linked from the top of the page? Or searching in a particular subforum with the search box at the bottom there?
![:) :)](https://amblesideonline.org/forum/images/smilies/smiley.gif)
Phyllis in Ukraine, with Jaan (AO grad), Raia (AO grad), Asya (age 16), Bogdan (age 13)