Ajax search – multilingual

Hi,
Really nice plugin! I use it on a multilingual website (wpml), and all works well in search widget. But I also have a search box in header. When I write into this one, I have this error:

Failed to load resource: the server responded with a status of 404 (OK)
https://******.com/fr/wp-admin/admin-ajax.php

Any suggestion?

https://www.ads-software.com/plugins/buddypress-global-search/