First time install - Error: "docker: invalid reference format: repository name must be lowercase"

[AaronSRS]

Hey everyone, writing here in the hopes of getting some help from the community.

I just installed Docker on a Raspberry Pi 4 (followed this tutorial) and have been having a bit of a hard time figuring out how to set up the alpine-qbittorrent-openvpn container. I should note that I have no experience with Docker whatsoever.

I did a sudo docker pull guillaumedsde/alpine-qbittorrent-openvpn:python which worked just fine, but I hit a snag right after that.
I customized the docker run command to

sudo docker run --cap-add=NET_ADMIN -d \
              -v /media/pi/My Passport/Downloads \
              -v /path/to/config/directory:/config \
              -v /etc/localtime:/etc/localtime:ro \
              -e OPENVPN_PROVIDER=NORDVPN \
              -e OPENVPN_CONFIG=ca_toronto \
              -e OPENVPN_USERNAME=my_user \
              -e OPENVPN_PASSWORD=my_pass \
              -e PUID=1000 \
              -e PGID=1000 \
              -e LAN=192.168.0.37/24 \
              -p 8080:8080 \
              guillaumedsde/alpine-qbittorrent-openvpn:python

but every time I turn to run it I get docker: invalid reference format: repository name must be lowercase.

Now, I know that -v /path/to/config/directory:/config \ is not valid, and I did remove that, but I am not sure what is supposed to go there. I also tried removing all arguments and just doing a sudo docker run guillaumedsde/alpine-qbittorrent-openvpn:python but obviously that fails and I get

... 
[cont-init.d] 02-setup-openvpn: executing... 
/var/run/s6/etc/cont-init.d/02-setup-openvpn: line 19: openvpn: Operation not permitted
...
[s6-finish] waiting for services.
[s6-finish] sending all processes the TERM signal.
[s6-finish] sending all processes the KILL signal and exiting.

Does anyone have any tips on how to troubleshoot it or get it running? Thanks!