Failed to load config.yml error message when first logging on to deployed site

[ItsEthanH]

Describe the bug
When deploying a project using DecapCMS, the first time you go to /admin/, an error message shows reading:

Error loading the CMS configuration
Config Errors:

Error: Failed to load config.yml (404)

Check your config.yml file.

It seems as if this is because the URL isn't formatted correctly. Going to /admin/ redirects me to:

https://www.domain.com/admin#/

When instead I should go to

https://www.domain.com/admin/#/

To Reproduce

1. Go to a project using Decap, without having logged in before (clearing cookies may help with this)
2. Navigate to the /admin/ route
3. Note the above error message, with the document URL path reading /admin#/
4. Change the path to /admin/#/
5. Note that this now works

Expected behavior
For a user to immediately go to /admin/#/

Screenshots

Broken path and error:

Applicable Versions:

• Netlify CMS version: ^2.0.0
• Git provider: Github
• OS: Windows 10
• Browser version Firefox 115.0.3 64bit
• Node.JS version: v20.3.1

CMS configuration
May not be relevant, as it's been replicated with a range of CMS configurations, however:

backend:
name: git-gateway
branch: main

local_backend: true
logo_url: https://codestitch.app/frontend/images/logo.png

media_folder: "public/assets/images/blog"
public_folder: "/assets/images/blog"

collections:
- name: "blog"
label: "Blog"
folder: "src/content/blog"
create: true
slug: "{{slug}}"
fields:
- { label: "Title", name: "title", widget: "string" }
- { label: "Description", name: "description", widget: "string" }
- { label: "Author", name: "author", widget: "string" }
- { label: "Date", name: "date", widget: "datetime" }
- { label: "Tags", name: "tags", widget: "list", default: ["post"] }
- { label: "Featured Image", name: "image", widget: "image" }
- { label: "Image Caption", name: "imageAlt", widget: "string" }
- { label: "Body", name: "body", widget: "markdown" }

[martinjagodic]

@ItsEthanH which SSG are you using?

[ItsEthanH]

Heya, it's eleventy :)

[martinjagodic]

I observed the same bug with the Hugo template: decaporg/one-click-hugo-cms#781

[fdb]

I had the same issue. It seems Decap is trying to load the config from the root path (/config.yml) instead of the admin path (/admin/config.yml).

[soonium]

I have the same issue also with 11ty.

[sukaikan]

Hi everyone, I am today trying to use that CMS, and showing the same problem. It showed me a 404 config.yml not found. Has anyone solved the problem? Thanks

[tonyd256]

Not sure if it's helpful, but I use Eleventy and had to manually pass through the config file in the build settings. For eleventy it was adding config.addPassthroughCopy({ "admin/config.yml": "admin/config.yml" }); to my .eleventy.js config file.