EventBridge Rule Testing doesn't work

Hello,

I'm trying to set up the eventbridge for custom events that my application will be raising. So I've been reading the documentation, got my eventbus created, added the API Destination and want to create a rule that should only forward events with a specific field to this destination. So according to the documentation, this is what an event would look like:

{
  "account": "123456789012",
  "detail-type": "Deployment History Notification",
  "source": "company.my-app",
  "detail": {
    "event": "deployment",
    "projectName": "app-that-got-deployed",
    "deploymentUrl": "https://myapp.com/api/deployments/:id.json",
    "version": "Tool 13.12.0"
  }
}

I've assumed this based on the documentation here: https://docs.aws.amazon.com/eventbridge/latest/userguide/eb-events.html So now I want to match anything from my account, and that's a deployment, so I set up the following pattern in the rule:

{
  "account": ["123456789012"],
  "detail": {
    "event": ["deployment"]
  }
}

But the rules page keeps telling me that the example doesn't match the pattern. Why not? What did I miss? The documentation I am basing myself on is this one: https://docs.aws.amazon.com/eventbridge/latest/userguide/eb-event-patterns.html