Think I worked it out....
Was messing around with plex and had the same problem.
I think its definitely a permission issue .
In windows I found out jellyfin group had permission to the folder i mounted but not anything within the folder.
So I went to permission for the dataset and selected
	
		
			
		
		
	
View attachment 66846
	
		
			
		
		
	
and it then started working.
Is there any problem with doing this?