I right click on the article, select retrieve metadata, it says cannot retrieve metadata, i ran an error report and submitted it as this post said to then entered the ID report as this post said to.
Not every PDF will be able to be recognized. It has to have readable text, and there has to either be an identifier (DOI, ISBN, etc.) on the first few pages or be in a fairly standard academic format.
If you think a PDF should work but it isn't and you can provide a link to the PDF online, we can take a look.
If you think a PDF should work but it isn't and you can provide a link to the PDF online, we can take a look.