Passing env variables to Ubuntu container

I’m working on a project and I’m having trouble passing env variables to an Ubuntu Docker container (tdarr_aio)

The env variables work fine with the Alpine container (tdarr). With tdarr_aio, using a command along these lines:

docker run -ti --rm \
 -v /media:/home/Tdarr/Media \
   -v /home/user/Documents/Tdarr:/home/Tdarr/Documents/Tdarr \
 -p 8265:8265 \
 -v TdarrData:/var/lib/mongodb \
 -v /etc/localtime:/etc/localtime:ro \
 -e "BASE=/URL_base_path"

Env variable ‘Base’ is not passed to the container.

What am I missing? The two Docker files are in the root of the repo:

Any help appreciated.