Hi @jdutant,
That plugin is not ready for OJS 3.2.1-x yet – see OJS version : 3.2.1.1 - Crossref deposit /Export XML problem **Unrecognized DAO PublishedArticleDAO!** · Issue #6071 · pkp/pkp-lib · GitHub for details.
Regards,
Alec Smecher
Public Knowledge Project Team