You'd need to tell us why it failed. Was there any error message? If the citations are not active the ref extractor won't work. You can try: https://anystyle.io/
Well, there was no any error message, it just said 0 reference were found. I mannually copy and paste the citation into the reference extractor , does it mean that it not active?
I'm not sure what you mean by "mannually copy and paste the citation into the reference extractor" — Reference Extractor takes a document that has existing Zotero or Mendeley citations.
If you didn't create the document with one of those, you'd use AnyStyle, linked above.
If the citations are not active the ref extractor won't work.
You can try: https://anystyle.io/
I'm not sure what you mean by "mannually copy and paste the citation into the reference extractor" — Reference Extractor takes a document that has existing Zotero or Mendeley citations.
If you didn't create the document with one of those, you'd use AnyStyle, linked above.