Failure is linking jabref to libreoffice writer

I am using Ubuntu 20, LibreOffice 7 and Jabref 5.1.
I have manually linked JabRef to soffice by supplying /usr/lib/libreoffice/program in the manual connect window since the original /usr/lib did not work.
I connected the document but when I insert a citation I only obtain [-].
What is wrong?
Thank you

Since something is inserted, I assume the connection is established. I think you might have a style with numbered citations. Try the refresh button in the libreoffice panel of jabref. I that works, you can also change the settings to automatically sync.

well, when I switched to author-date, there was an insertion. maybe is the style that is broken…

It might not be an issue of your style, but a result of the way JabRef syncs numbered citations. A very similar issue is reported at: