"Not Found" for simple org-name.github.io "github" provider setup

[eduncan911]

Describe the bug

There are 5 to 6 existing issues, mostly closed, stating the "Not Found" error - and none of them apply to my simple default usecase.

Upon clicking "Login with GitHub", we get a popup that says, "Not Found."

I am the organization admin, and have full access to this repo.

To Reproduce

1. Setup an Org to have "org-name.github.io"
2. Deploy /admin with the following configuration file below.
3. goto /admin, and click Login with GitHub. "Not Found" pops up.

Decap CMS setup:

backend:
  name: github
  repo: fabreeko/fabreeko.github.io
  branch: main
  squash_merges: true

Expected behavior

I get the standard "This site wants to login with Github..." popup that usually shows when signing in with Github.

Screenshots

Applicable Versions:

• decap-cms-app 3.6.3
• bootstrap.js:52 decap-cms-core 3.6.2
• index.js:27 decap-cms 3.6.3
• Git provider: github

CMS configuration

https://github.com/Fabreeko/fabreeko.github.io/blob/main/docs/admin/config.yml

Additional context

I would not open an issue if I didn't search the interwebs, these github issues, and forum posts already. The usecase is a very simple deployment using org-name.github.io.

Note, it is a Github Organization I am attempting to use.