If the permission are ok, check to see if the folder has files other than multimedia ones. You might get an error that won't show up in logs. To check switch to emby user and run find command:
su -s /bin/bash emby emby@raspberrypi:~ $ find /media/touro -ls > /dev/null find: ‘/media/touro/antisa-desktop/duplicity-full.20190920T085932Z.vol1847.difftar.gpg’: Input/output error find: ‘/media/touro/antisa-desktop/duplicity-full.20190920T085932Z.vol1848.difftar.gpg’: Input/output error
Errors above caused the issue with scanning the folder on external ntfs formatted usb disk. Remove the files or move the multimedia files to another folder.