Codemagic Build Fail because "GitHub Personal Access Token is not set"

I have been trying to use codemagic to make a build of my React/Electron application for a Mac environment as my current development environment is Windows.

It almost gets through the build, but then it fails with this status code (1):

⨯ GitHub Personal Access Token is not set, neither programmatically, nor using env "GH_TOKEN"

I've tried to set GH_TOKEN programmatically, as "process.env.GH_TOKEN=XXXX" where I've used my personal access token. I've tried adding it to my .env file, I've also tried to put it in the yaml file.

  workflows: 
    macos-build:
      name: macOS Build
      instance_type: mac_pro
      environment:
        groups:
          - prod 
        node: 16.14.0

      scripts:
        - name: Injecting env vars
          script: echo "REACT_APP_API_KEY=$REACT_APP_API_KEY" >> .env
        - name: Installing packages
          script: yarn install
        - name: Building Applications - React
          script: GH_TOKEN=XXXXXX yarn build
        - name: Building Application - Electron
          script: yarn electron-builder -m -c.extraMetadata.main=build/electron.js 

      artifacts:
        - out/make/*.dmg

I tried to add it as a single script as well, and I continue to get the error. The only time I don't get the error is if I add:

--publish=never

to the electron-builder tag. But then I am left with no artifact.

Can someone tell me what I'm doing wrong?

Thanks.