Steps to reproduce:
$ docker run -t --entrypoint /bin/bash kolab/guam -s
[root@0ba5806f085f guam.git]# erl -pa apps/*/ebin deps/*/ebin -config app -s kolab_guam
Docker image is built from https://github.com/kanarip/kolab-atomicapp/blob/master/03-guam/Dockerfile
The original entrypoint takes in environment variables `KOLAB_IMAPF_EXT_SERVICE_HOST` (the IP address of the target IMAP server), and sets `{ tls, true }` in `/root/guam.git/app.config`. The aforementioned example command-line does neither of the substitions.
#guam ends up listening on `0.0.0.0:1936` only.