ServiceNow REST API 408 Timeout on Genesys Cloud Digital Channel Webhook

General Discussion
1

Stumbled on a weird bug today with the webhook payload delivery to our ServiceNow instance during peak London hours.

The Genesys Cloud outbound webhook configured for digital channel message events is consistently failing with a 408 Request Timeout when hitting the ServiceNow REST API endpoint /api/now/table/incident. The payload size is minimal (under 2KB), and the ServiceNow instance health checks show no latency issues from other integrations. The webhook configuration uses Basic Auth, and the timeout is set to the default 30 seconds. Interestingly, this only happens for messaging transcripts that exceed 500 words in the text field. Smaller messages process successfully. The error log in Genesys Cloud shows HTTP/1.1 408 Request Timeout with no retry mechanism triggering despite the retry policy being set to exponential_backoff. Is there a known limitation or hidden header requirement for large text payloads in digital channel webhooks that might cause the HTTP client to drop the connection prematurely before ServiceNow can process the body?

2

If I remember correctly, ServiceNow often drops payloads that don’t explicitly declare the content type, which breaks the chain of custody for legal holds.

  • Add Content-Type: application/json to the webhook headers.
  • Verify the ServiceNow table allows anonymous or token-based POST requests.
3

If I remember right, the 408 is often a TLS handshake delay rather than payload size.

  • Verify the ServiceNow endpoint accepts TLS 1.2 or higher.
  • Check if Genesys Cloud is hitting a private IP that requires explicit allow-listing.