Issue

When sending a test event to the Marketo Static Lists (Actions) destination in Segment, you may encounter a 400 error in the Event Tester. This error occurs because the required List Id field (context.personas.external_audience_id) is missing from the test payload.

Product

Twilio Segment

Environment

Segment Console

Cause

The Marketo Static Lists (Actions) destination requires a valid List Id in the payload. During normal event processing, Segment automatically manages the List Id field. However, when using the Event Tester, this automatic population does not occur. If the test payload does not include a valid List Id at context.personas.external_audience_id, the Event Tester returns a 400 error.

Resolution

1. Open the Event Tester and manually add a valid List Id to your test payload at the following key path: context.personas.external_audience_id
2. Ensure the List Id matches a valid static list in your Marketo account.
3. Re-run the test event. The Event Tester should now process the event successfully.

Additional Information 

For more details, see the Segment documentation on Using Marketo Static Lists (Actions) with the Event Tester.