I am no expert in this but have you checked the box where the files are stored. The box i mean is "share files and folders with other users"
Like i say i am no expert but i am giving it a wild stab in the dark.
OnePlus 5T review: Hands-on
Illustrator Andrés Lozano on his improv line work, brazen use of colours & hand sketching
iPhone X review
Comment envoyer gratuitement des gros fichiers ?