Joplin Server pre-release is now available

Hi,
I made another post (Original post) but this is maybe a better place for it since it relates to Joplin server.
I've installed joplin-server as a docker container and use the app on MacOS.
When configuring the app, in preferences/synchronisation I get:
request to http://myserver.local:22300/api/sessions failed, reason: connect EBADF 192.168.0.10:22300 (Code EBADF).
Browsing to the URL I get:
error "Not allowed: GET api/sessions"
I have tried with different image versions (stable, latest) with the same result.
I tried from iOS and have the same result.
I tried with the admin account or a user account, but still don't understand why just browsing to:
http://myserver.local:22300/api/sessions even without authentication fails.
Does the server require to run in https ?