Missing Master Key Error Github Action with test.key stored as a secret

I am going crazy with Rails Credentials! I have a Missing Master Key Error when launching my Github Action test.

I have

1. generated credentials/test.key and credentials/test.yml.enc with rails credential:edit -e test command,

2. stored the content of test.key in a GITHUB Actions Secret

3. referenced it in my Github Action

   env:
     RAILS_ENV: test      
     RAILS_MASTER_KEY: ${{ secrets.RAILS_MASTER_KEY }}
   

Still say "Missing Key"... I also have done the same in production (as before the master.key was stored on Github!!)