[Koha] opac / no results for a search

Hi! We use koha 3.12 and we have today a problem with our opac. When we do a search, it gives no results (but, the professional search work fine). I run zebra as a user named koha and the ownership of files are ok. I've checked some systempreferences as "hidelostitem" and "opacsuppression": all is ok. An idea? Best regards Samuel