Can't see uploaded files in Media Library

Hi.

I’m trying to include any image or pdf file that was previous uploaded into any page through the “add media” button. When I click on it a new window appears with JUST SOME of the items that already were uploaded.

I can see all the files in my uploads folder.

If I try to add a new item that was already uploaded but it’s not found in the media library, wordpress adds the number 1 at the end of the name of the file, because there’s already an other file with that name despite it’s not listed in the media library.

Why can’t I see the new items int the media library when I’m editing a page??

Thanks