Folder permission denied on server folder

I'm using a Raspberry Pi as a remote PLEX server, connected to my pi is an external hard drive with all my media saved on it. This all works great except when I try to open the external hard drive folder on my Mac, I get a permission denied you do not have permission to see its contents error message. If I SSH in using terminal then I can open the external hard drive folder just fine, however if I do a cmd + k in finder to connect to a server then enter smb://ip address when I try open the same folder I get the error message. I've done an ls - l and get the following result so I'm a bit stuck really. total 256 drwxrwxrwx 1 pi pi 262144 Jan 1 1970 'My Passport' I set up samba using the following guide; https://www.raspberrypi.org/magpi/samba-file-server/ My external drive is mounted at /media/pi/'My Passport' the end of my smb.conf file looks like