I’ve checked out provided earlier information and it looks like the issue is related to your Traefik configuration.
Please try adding these labels to the .yml file which runs the container with Document Server:
- "traefik.http.routers.ds.middlewares=onlyoffice-headers"
- "traefik.http.middlewares.onlyoffice-headers.headers.customrequestheaders.X-Forwarded-Proto=https"
- "traefik.http.middlewares.onlyoffice-headers.headers.accessControlAllowOrigin=*"
Please use these labels to run a “clear” test, i.e. without your previously used workaround.
Looking forward to your feedback.