Google email markup not showing

Question

I'm trying to make a simple view action using Email markup from Google inside my emails (https://developers.google.com/gmail/markup/reference/go-to-action#view_action)

I use this ld+json inside my email template

<script type="application/ld+json">
{
  "@context": "http://schema.org",
  "@type": "EmailMessage",
  "potentialAction": {
    "@type": "ViewAction",
    "target": http://google.com",
    "url": "http://google.com",
    "name": See ticket"
  }
}
</script>

I used Google email markup tester to valid this code.

I use registred emails (https://developers.google.com/gmail/markup/registering-with-google)

But I still can show the emails markup on Gmail.

Did I miss something ?

Do you have any clues ?

Thanks