Does it work on 'modern' posts?
Tried searching for 'tardigrades', as I know they were mentioned in a recent post, but it retuns nothing.
Just tried searching for 'predator' (mentioned this morning), and all the results are from 2010-2013, with one post from 2017.
It could be part of the software glitches that we need to get fixed. Once I've got the new site sorted out I'll get our webguy to run the software upgrade here and everything should start working again!