When trying to initiate the indexing from the backend component dashboard I get a popup with:
Duplicate entry '1890-11' for key 'taxonomy_map_id'
Could you backup your site first and share the cPanel of your site?
I fixed the issue on your site. Kindly check.
File was changed: /components/com_jak2filter/helpers/helper.php
cPanel login is the same as ftp login above. Just add the :2083 port to the end of the URL.