warning : filesize

Can i somehow fix this warning?

Warning: filesize(): stat failed for /home/storage/6/b1/7c/webrural2/public_html/wp-content/uploads/2018/11/18-anos-depois-como-está-trabalhando-a-maioria-dos-produtores-rurais-no-Brasil.pdf in /home/storage/6/b1/7c/webrural2/public_html/wp-content/plugins/better-file-download/public/class-better-file-download-public.php on line 428

The page I need help with: [log in to see the link]