First log in to get the JSESSIONID
cookie and then post the item (I'm using httpie instead of curl):
$ http -f POST https://dspacetest.cgiar.org/rest/login [email protected] password=fuuuu
$ http https://dspacetest.cgiar.org/rest/status Cookie:JSESSIONID=EABAC9EFF942028AA52DFDA16DBCAFDE
$ http POST https://dspacetest.cgiar.org/rest/collections/f10ad667-2746-4705-8b16-4439abe61d22/items Cookie:JSESSIONID=EABAC9EFF942028AA52DFDA16DBCAFDE < item-object.json
HTTP/1.1 200 OK
Connection: keep-alive
Content-Encoding: gzip