I am trying to run Silex locally in a docker container and publish to GitHub Pages, but I receive an error when trying to get Silex logged in.

How I am running my container:

docker run -it --name silex --restart=always -d \
 -e "ENABLE_HOSTING_GH_PAGES=true" \
 -e "GITHUB_CLIENT_ID=xxxxx" \
-e "GITHUB_CLIENT_SECRET=xxxxx" \
-v /home/user/website:/root/website  \
-e "SILEX_DEBUG=true" \
-p 6807:6805 \
silexlabs/silex:v2.7.63

In GitHub, the Application Callback URL is:

http://localhost:6807/github/oauth_callback

When I try to login to publish, I get this in the address bar:

http://localhost:6807/github/oauth_callback?error=redirect_uri_mismatch&error_description=The+redirect_uri+MUST+match+the+registered+callback+URL+for+this+application.&error_uri=https%3A%2F%2Fdocs.github.com%2Fapps%2Fmanaging-oauth-apps%2Ftroubleshooting-authorization-request-errors%2F%23redirect-uri-mismatch&state=gka5ry6oaqn

and the response body has:

Cannot GET /github/oauth_callback

This error seems to suggest the wrong URL is configured in GitHub, but I can't find any references in documentation or otherwise to what this callback URL should be for publishing. Please let me know if there is any other information I can provide to help determine what's going wrong. Thanks!