Thank you ! I found the solution !
There was a problem with another plugin : “relevanssi”. By disabling this plugin, the search worked again. The problem is that “relevanssi” is very useful for increasing the relevance of the wordpress search results. And WPDM is really useful for searching files. Do you know how I could do to make WPDM and relevanssi live together?
I did some research (Google) before asking this question and I found a post about this problem but I can not open the page because I am not a WPDM user pro … ๐
Thank’s
WPDM Search and Relevanssi