GitLab CI: Variables not working

I have set up some variables for my CI script at https://gitlab.com///-/settings/ci_cd

And I am trying to use them in .gitlab-ci-yml but it is as they are not parsed? If I put the content from the variables directly into the script, it works, but it fails when I refer them:

 $ npm-cli-login -u ${WEBIX_USER} -p ${WEBIX_PASSWORD} -e ${WEBIX_EMAIL} -r http://npm.webix.com -s @xbs
 /usr/lib/node_modules/npm-cli-login/lib/index.js:11
             throw new Error(err);
             ^

I read somewhere that it is intended that the variable name is displayed, but it doesn't change the fact that the login fails – and only when I refer variables, not when I hardcode the values.