PUT with REST API to Docker-based GitLab fails with 405 response

I have a GitLab server running in a Docker container using the gitlab/gitlab-ce as my base (and currently not modifying it in any way beyond configuring the GITLAB_SECRETS_DB_KEY_BASE and hostname.

With this server I can use the REST API with GET methods but my attempts to use PUT methods always result in response 405, operation not allowed.

This is a server running within a single user’s machine with not intention of or need for wider exposure so I haven’t tried setting up SSH (for one thing, in this environment, setting up SSH keys would be a pain where otherwise there’s no need for that level of security.

Looking through all the docs I could find I don’t see any indication that HTTPS is required for PUT actions.

This is on OS X (and Windows), so the REST call is coming from a different host than the GitLab server, but I wouldn’t expect that to be an issue.

Is there some configuration detail that is required to allow PUT to work or does it have to be non-obvious user error?