why would Codeclimate be unable to show gpa?

Question

What are the possible reasons a code climate gap badge would show up as a question mark/unknown?

The other badges are working however, I can see number of issues, and % LoC Covered badges.

Here's my .codeclimate.yml file

engines:
  rubocop:
    enabled: true
  eslint:
    enabled: true
  csslint:
    enabled: true
  duplication:
    enabled: true
    config:
      languages:
      - ruby:
      - javascript:
exclude_paths:
- "test/"
- "coverage/"
- "doc/"
- "bin/"

Answer 1

In think You are missing this from your .codeclimate file:

ratings:
  paths:
  - Gemfile.lock
  - "**.css"
  - "**.js"
  - "**.jsx"
  - "**.rb"

You can read about it more here: https://docs.codeclimate.com/v1.0/docs/ratings

You also need to make sure your files have UTF-8 encoding.