Assigning DOIs in CrossRef Plugin

I’m trying to assign DOIs to the articles in an issue that’s already been published, but when I go into the CrossRef Plugin, I don’t see any articles listed there. Do I need to unpublish the issue and then assign the DOIs? Or could the editor have uploaded the article files incorrectly (they did this while I was away, so I don’t know exactly what steps they took)?

Note:We’re using OJS 3!


If plugin setting for prefix/suffix had been done, you may assign doi to issue through visiting respective issue (Not through plugin) in identifier tab and article doi can be assign by clicking on either schedule for publication or metadata of respective article through identifier tab.