since yesterday we verified that DataCite DOI registration is not working.
MDS API get an error saying "412 Precondition failed - metadata must be uploaded first". I think that the explication is that, until January 7 you could create DOIs before (or whitout) sending metadata too, but now you must to create DOIs only after uploading metadata for the article.
Note that MDS documentation ever stated that you have to send metadata with the DOI create request, but you still create DOIS with any metadata.
Now the API works only as described in the docs.
When I register articles, I ever get "is Ref Quality = false".
Do you know why?