I wanted to put in DOI number using QuickSubmit plugin, but the information I got is:The given DOI suffix is already in use for another published item. Please enter a unique DOI suffix for each item.
The situation may be the result of some misunderstanding with the editor who previously tried to publish the issue of the journal on OJS platform.
So, do duplicate articles of the articles that you’re trying to upload via QuickSubmit already exist in your journal? I’m not sure I totally understand the situation.