Samba share no access

My docker-compose script creates a samba share that I am able to access from my windows computer, although I have no permissions to write in this folder. I have a connection with the use plex that is mentioned in the script. How can I get write access to the share? I have tried for hours, but still no luck.

version: ‘3.4’

services:
samba:
image: dperson/samba
environment:
TZ: ‘EST5EDT’
networks:
- default
ports:
- “137:137/udp”
- “138:138/udp”
- “139:139/tcp”
- “445:445/tcp”
read_only: true
tmpfs:
- /tmp
restart: unless-stopped
stdin_open: true
tty: true
volumes:
- /home/pi/plex/mnt:/mnt:z
- /home/pi/plex/mnt2:/mnt2:z

command: '-s "plex;/mnt" -s "Plex Volume;/mnt2;yes;no;no;plex" -u "plex;plex" -p'

Don’t know why the last line has a box around, it’s the last line of the compose script.

By the way, the share doesn’t have to be protected by a username/password, if it is possible it may allow all users R/W