How are you trying to feed the products into the Recs engine? Are you passing values on the page (using targetPageParams() function), using feeds (csv, google product feed, Analytics Classification) or via API? Have you been uploading the products to "all environments" or to a specific one?
What shows up on the Catalog Search page (Target > Recommendations > Catalog Search) when you search for a product?
We have passed the products in the targetPAgepArams() method with the target global mbox, since this was not working as expected , we even tried using the mboxUpdate() and mboxDefine() method with a dynamic mbox.
I have shared a document explaining the steps i followed.