HTTP 503 from lms during cms login


I am receiving an error from studio when I try to login. When I click ‘sign in’ I am redirected to the lms login page, where I successfully login, before being redirected back to studio, where I receive an error message.

Looking at the tutor cms logs (, the first error is:

requests.exceptions.HTTPError: 503 Server Error: Service Unavailable for url: http://lms:8000/oauth2/access_token

with the final error:

social_core.exceptions.AuthUnreachableProvider: The authentication provider could not be reached

There are no errors in the lms logs. Lms login works fine.

I am running tutor 14.2.3 with an nginx reverse proxy, which is run behind a network proxy. Tutor is configured with , CADDY_HTTP_PORT= ENABLE_HTTPS=true ENABLE_WEB_PROXY=false and a tutor plugin:

from tutor import hooks

    "SOCIAL_AUTH_PROXIES = {'https': ''}"

Any help would be greatly appreciated.

Are you able to reach the lms container from the cms container?

Something like:

tutor local exec cms bash
curl http://lms:8000/oauth2/access_token

Thank you for your response. I am unable to reach the lms container from the cms container. I got the following status codes from curl

$ docker exec -it tutor_local-cms-1 /bin/bash

cms $ curl -I http://lms:8000/oauth2/access_token
HTTP/1.1 503 Service Unavailable

cms $ curl -I https://lms:8000/oauth2/access_token
HTTP/1.1 403 Forbidden

cms $ curl -I
HTTP/1.1 200 Connection established

Could this be a proxy issue? I have experienced multiple proxy issues during setup e.g. I had to add proxy ENV settings manually to the top of each Dockerfile.

ENV http_proxy
ENV https_proxy