Can anyone clarify the expected behavior of the ServiceNow Data Action when attempting to upload large JSON payloads via the api/now/attachment/file endpoint? The current Genesys Cloud environment is running Release 2025-01 (v13.3) in the AWS London region. We have an Architect flow designed to capture chat transcripts from digital channels and push them directly to a ServiceNow incident record. The flow utilizes a Data Action configured with OAuth2 credentials that have been verified as active and possessing the admin role in ServiceNow. The issue arises specifically when the transcript exceeds 50KB. The Data Action returns a 403 Forbidden error, whereas manual POST requests from Postman using the same credentials and payload structure succeed without issue. The request headers include Content-Type: application/json and Accept: application/json. The ServiceNow instance is Paris (PAR) and is configured to accept webhooks from the Genesys Cloud IP ranges. The error response body from ServiceNow indicates “User does not have permission to perform this operation,” which is contradictory given the token scope. We have cross-referenced the Genesys Cloud documentation for Data Actions and confirmed that the body parameter is correctly formatted as a stringified JSON object containing the upload and table_api_name fields. The flow node configuration shows no validation errors. The timestamp of the failure correlates with high-traffic periods in the London timezone, suggesting a potential rate-limiting or payload inspection issue on the Genesys Cloud side before the request reaches ServiceNow. The webhook payload for the initial conversation event contains the full transcript, which is then processed by a JavaScript step to extract the relevant text before passing it to the Data Action. We have disabled all custom scripts on the ServiceNow incident table to rule out business rule interference. The problem persists across multiple test agents and different digital channel sources (Web Chat and WhatsApp). Is there a known limitation on the Data Action payload size or a specific header requirement for binary attachments that is not documented? We need a reliable method to attach these transcripts without falling back to a custom webhook implementation that requires manual token management.