Error: "Container element not specified for card component"

[Bergrebell]

When I try to implement one of the examples in Nuxt JS (which extends VueJS) - I get the error "Container element not specified for card component" and the component doesn't get rendered.

this is my page where I import CardTest where CardTest is just one of the examples:

<template>
  <div class="test">
    Test
    <card-test></card-test>
  </div>
</template>

<script>
import CardTest from '~/components/CardTest'

export default {
  components: {
    CardTest
  },

  mounted() {
    window.Chargebee.init({
      site: 'xxx-test',
      publishableKey: 'test_xxx'
    })
  }
}
</script>