OH, I see 🙂
Well, by default (as you can see in the docker.compose.yml file, in the services.apiserver.volumes section), the server will look for extra configuration files in the host's file system under /opt/clearml/config . If it's not there, no harm is done.
You can simply shut down the server, create the /opt/cleaml/config folder (make sure it has the same permissions as the rest of the /opt/clearml folder where the server is currently deployed), add the required apiserver.conf file, and start the server up again.
By the way, which server version are you using?