I am working at another computer within my institution, rather than at my desk. I downloaded the Zotero Firefox add on onto this computer, signed in online, and synced. My libraries downloaded, but only some of the pdfs are available. The others have a hollow blue dot, rather than the solid blue dot indicating a pdf is attached, and I am told that the file could not be found. I do not understand why some pdfs are available but not others, nor why, since I am connecting through the same university library, I would not have access. The only thing I could think of was needing to add a saved proxy to the add on. Am I on the right track?