Outbound Campaign List API 400 Bad Request with ServiceNow Ticket Reference in Custom Fields

Context:
Just noticed that our outbound dialing campaign list generation is failing when attempting to enrich contact records with ServiceNow ticket references via a Data Action webhook prior to the dial attempt. We are running Genesys Cloud version 23.4 in the eu-west-1 region, aligned with our ServiceNow instance in the same timezone (Europe/London). The flow architecture involves a Predictive Outbound campaign pulling from a database connector. Before the dial step, a Data Action is triggered to fetch the latest ticket status from ServiceNow using the GET /api/v3/outbound/campaign-lists endpoint logic, but specifically, we are trying to append custom attributes to the contact record that map to ServiceNow sys_id values.

The issue manifests as a 400 Bad Request error within the Genesys Cloud logs, specifically pointing to a validation failure on the custom_attributes payload sent to the ServiceNow REST API endpoint configured in the Data Action. The error message returned is "message": "Invalid input for field 'u_gc_contact_id'". This is puzzling because the u_gc_contact_id field in ServiceNow is a standard String field with a maximum length of 40 characters, and the Genesys Cloud contact ID is well within this limit. We have verified that the ServiceNow OAuth credentials are valid and that the integration user has write access to the incident table.

The webhook payload being sent looks like this:

{
 "sysparm_query": "sys_id=ABC123",
 "custom_attributes": {
 "u_gc_contact_id": "contact_uuid_here",
 "u_gc_campaign_id": "campaign_uuid_here"
 }
}

We suspect there might be a mismatch in how Genesys Cloud serializes the custom attributes for the outbound campaign list enrichment versus what ServiceNow expects for nested objects in a PUT request. The documentation for Data Actions mentions flattening complex objects, but it is unclear if this applies to outbound campaign contact enrichment.

Question:
Can anyone clarify the exact payload structure required for passing custom attributes from a Genesys Cloud outbound campaign list to a ServiceNow incident via a Data Action? Specifically, is there a known limitation or specific formatting requirement for custom_attributes when used in the context of outbound dialing contact enrichment that differs from standard inbound bot flows? We need to ensure the ServiceNow ticket reference is correctly linked to the Genesys contact for accurate reporting and screen pop functionality.

Ah, yeah, this is a known issue with data enrichment timing in predictive outbound flows. The 400 Bad Request typically occurs when the Data Action webhook attempts to write to a custom field that has not yet been fully indexed or validated by the Campaign List service before the dial step initiates. While the previous suggestion regarding timeout increases is valid for network latency, it does not address the structural mismatch between ServiceNow payload schemas and Genesys Cloud’s strict JSON validation for campaign lists.

The core problem lies in how the Data Action handles null values or unexpected string formats from ServiceNow. If the ticket reference is empty, the webhook may return an empty string "" instead of a null value, which the Campaign List API rejects as an invalid type for certain custom field definitions.

To resolve this, the Data Action configuration must include explicit null-handling logic. Ensure the “On Failure” behavior is set to “Continue” rather than “Stop Flow,” and add a Set Variable step immediately after the webhook to sanitize the input.

The sanitized variable should then be mapped to the Campaign List custom field. This ensures that only valid, non-empty references are pushed to the outbound list. Additionally, verify that the custom field in Genesys Cloud is defined as a “String” type with a maximum length that accommodates the full ServiceNow ticket ID format. If the field is defined as “Integer” or “Number,” any alphanumeric characters in the ticket reference will trigger a 400 error. Adjusting the field type in the Admin > Campaigns > Lists configuration usually resolves this schema mismatch.