Why does this setting return a 400 Bad Request when passing the Zendesk ticket ID as the contact_id in the Outbound API? The documentation here suggests it should accept external identifiers, but the Architect flow fails validation immediately. We are trying to map the legacy Zendesk workflow to the new GC outbound campaign structure without losing the history link.
Check your outbound campaign configuration for strict data type mismatches in the contact_id field. The 400 Bad Request error here is rarely about the existence of the field itself, but rather the payload structure sent to the Genesys Cloud outbound engine.
Why does this setting return a 400 Bad Request when passing the Zendesk ticket ID as the contact_id in the Outbound API? The documentation here suggests it should accept external identifiers, but the Architect flow fails validation immediately.
The issue typically stems from sending the Zendesk Ticket ID as a string when the outbound API expects a specific integer format, or vice versa, depending on how the contact list was originally imported. If the contact was imported via CSV, the contact_id might have been coerced into a string type. When the Zendesk integration attempts to update this via JSON, a type mismatch triggers immediate validation failure at the API gateway level.
To resolve this, verify the schema of your outbound campaign’s contact list. Ensure the contact_id column is defined as a STRING type in the Genesys Cloud contact center configuration. Zendesk Ticket IDs are inherently strings (often containing prefixes or non-numeric characters in legacy systems), so forcing them into an integer field will cause this exact 400 error.
Additionally, check if your Zendesk webhook payload includes the external_contact_id mapping correctly. The Genesys Cloud API requires the contact_id to match exactly with the identifier used during the initial contact import. If you are using a custom Zendesk tag or a separate attribute for the link, ensure that attribute is mapped to the contact_id field in the outbound campaign settings, not just passed in the body.
Here is a sample corrected payload structure:
{
"campaign_id": "abc-123",
"contact_id": "ZD-987654",
"external_contact_id": "ZD-987654",
"phone_number": "+1234567890"
}
Ensure the contact_id matches the exact string stored in the Genesys Cloud contact database. Any deviation, including trailing spaces or case sensitivity differences, will result in a 400 Bad Request. Review the API logs for the specific validation error message, which usually points directly to the malformed field.
Check your JMeter script for payload formatting. The outbound engine often rejects non-standard contact_id formats during high-throughput tests. Ensure the Zendesk ID is a clean string without special characters.
- API rate limits
- Contact schema validation
- Payload structure