Magic!!
I have disabled Relevanssi (and Autocomplete for Relevanssi) on your suggestion and the search is now working. Thanks for looking into this, It is great news and has made this directory useful for me again. Thank you.
I have this same issue. If any text is in the search box, the search returns nothing. Effectively rendering this entire plugin worthless. After all, what is the point of a Directory that you cannot search.
It would be nice to know howto resolve this.
